644 lines
18 KiB
JavaScript
644 lines
18 KiB
JavaScript
"use strict";
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const assert = require("assert");
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const util = require("./util");
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const startsWithNoLookaheadToken = util.startsWithNoLookaheadToken;
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function FastPath(value) {
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assert.ok(this instanceof FastPath);
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this.stack = [value];
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}
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// The name of the current property is always the penultimate element of
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// this.stack, and always a String.
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FastPath.prototype.getName = function getName() {
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const s = this.stack;
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const len = s.length;
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if (len > 1) {
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return s[len - 2];
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}
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// Since the name is always a string, null is a safe sentinel value to
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// return if we do not know the name of the (root) value.
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return null;
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};
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// The value of the current property is always the final element of
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// this.stack.
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FastPath.prototype.getValue = function getValue() {
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const s = this.stack;
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return s[s.length - 1];
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};
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function getNodeHelper(path, count) {
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const s = path.stack;
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for (let i = s.length - 1; i >= 0; i -= 2) {
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const value = s[i];
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if (value && !Array.isArray(value) && --count < 0) {
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return value;
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}
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}
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return null;
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}
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FastPath.prototype.getNode = function getNode(count) {
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return getNodeHelper(this, ~~count);
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};
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FastPath.prototype.getParentNode = function getParentNode(count) {
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return getNodeHelper(this, ~~count + 1);
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};
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// Temporarily push properties named by string arguments given after the
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// callback function onto this.stack, then call the callback with a
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// reference to this (modified) FastPath object. Note that the stack will
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// be restored to its original state after the callback is finished, so it
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// is probably a mistake to retain a reference to the path.
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FastPath.prototype.call = function call(callback /*, name1, name2, ... */) {
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const s = this.stack;
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const origLen = s.length;
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let value = s[origLen - 1];
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const argc = arguments.length;
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for (let i = 1; i < argc; ++i) {
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const name = arguments[i];
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value = value[name];
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s.push(name, value);
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}
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const result = callback(this);
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s.length = origLen;
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return result;
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};
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// Similar to FastPath.prototype.call, except that the value obtained by
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// accessing this.getValue()[name1][name2]... should be array-like. The
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// callback will be called with a reference to this path object for each
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// element of the array.
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FastPath.prototype.each = function each(callback /*, name1, name2, ... */) {
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const s = this.stack;
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const origLen = s.length;
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let value = s[origLen - 1];
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const argc = arguments.length;
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for (let i = 1; i < argc; ++i) {
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const name = arguments[i];
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value = value[name];
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s.push(name, value);
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}
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for (let i = 0; i < value.length; ++i) {
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if (i in value) {
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s.push(i, value[i]);
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// If the callback needs to know the value of i, call
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// path.getName(), assuming path is the parameter name.
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callback(this);
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s.length -= 2;
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}
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}
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s.length = origLen;
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};
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// Similar to FastPath.prototype.each, except that the results of the
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// callback function invocations are stored in an array and returned at
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// the end of the iteration.
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FastPath.prototype.map = function map(callback /*, name1, name2, ... */) {
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const s = this.stack;
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const origLen = s.length;
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let value = s[origLen - 1];
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const argc = arguments.length;
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for (let i = 1; i < argc; ++i) {
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const name = arguments[i];
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value = value[name];
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s.push(name, value);
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}
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const result = new Array(value.length);
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for (let i = 0; i < value.length; ++i) {
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if (i in value) {
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s.push(i, value[i]);
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result[i] = callback(this, i);
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s.length -= 2;
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}
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}
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s.length = origLen;
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return result;
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};
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FastPath.prototype.needsParens = function(options) {
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const parent = this.getParentNode();
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if (!parent) {
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return false;
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}
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const name = this.getName();
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const node = this.getNode();
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// If the value of this path is some child of a Node and not a Node
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// itself, then it doesn't need parentheses. Only Node objects (in
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// fact, only Expression nodes) need parentheses.
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if (this.getValue() !== node) {
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return false;
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}
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// Only statements don't need parentheses.
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if (isStatement(node)) {
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return false;
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}
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// Identifiers never need parentheses.
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if (node.type === "Identifier") {
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return false;
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}
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if (parent.type === "ParenthesizedExpression") {
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return false;
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}
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// Add parens around the extends clause of a class. It is needed for almost
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// all expressions.
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if (
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(parent.type === "ClassDeclaration" || parent.type === "ClassExpression") &&
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parent.superClass === node &&
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(node.type === "ArrowFunctionExpression" ||
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node.type === "AssignmentExpression" ||
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node.type === "AwaitExpression" ||
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node.type === "BinaryExpression" ||
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node.type === "ConditionalExpression" ||
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node.type === "LogicalExpression" ||
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node.type === "NewExpression" ||
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node.type === "ObjectExpression" ||
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node.type === "ParenthesizedExpression" ||
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node.type === "SequenceExpression" ||
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node.type === "TaggedTemplateExpression" ||
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node.type === "UnaryExpression" ||
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node.type === "UpdateExpression" ||
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node.type === "YieldExpression")
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) {
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return true;
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}
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if (
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(parent.type === "ArrowFunctionExpression" &&
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parent.body === node &&
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node.type !== "SequenceExpression" && // these have parens added anyway
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startsWithNoLookaheadToken(node, /* forbidFunctionAndClass */ false)) ||
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(parent.type === "ExpressionStatement" &&
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startsWithNoLookaheadToken(node, /* forbidFunctionAndClass */ true))
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) {
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return true;
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}
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switch (node.type) {
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case "CallExpression": {
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let firstParentNotMemberExpression = parent;
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let i = 0;
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while (
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firstParentNotMemberExpression &&
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firstParentNotMemberExpression.type === "MemberExpression"
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) {
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firstParentNotMemberExpression = this.getParentNode(++i);
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}
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if (
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firstParentNotMemberExpression.type === "NewExpression" &&
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firstParentNotMemberExpression.callee === this.getParentNode(i - 1)
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) {
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return true;
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}
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return false;
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}
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case "SpreadElement":
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case "SpreadProperty":
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return (
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parent.type === "MemberExpression" &&
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name === "object" &&
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parent.object === node
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);
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case "UpdateExpression":
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if (parent.type === "UnaryExpression") {
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return (
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node.prefix &&
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((node.operator === "++" && parent.operator === "+") ||
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(node.operator === "--" && parent.operator === "-"))
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);
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}
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// else fallthrough
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case "UnaryExpression":
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switch (parent.type) {
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case "UnaryExpression":
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return (
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node.operator === parent.operator &&
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(node.operator === "+" || node.operator === "-")
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);
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case "MemberExpression":
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return name === "object" && parent.object === node;
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case "TaggedTemplateExpression":
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return true;
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case "NewExpression":
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case "CallExpression":
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return name === "callee" && parent.callee === node;
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case "BinaryExpression":
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return parent.operator === "**" && name === "left";
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default:
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return false;
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}
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case "BinaryExpression": {
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if (parent.type === "UpdateExpression") {
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return true;
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}
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const isLeftOfAForStatement = node => {
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let i = 0;
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while (node) {
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const parent = this.getParentNode(i++);
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if (!parent) {
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return false;
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}
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if (parent.type === "ForStatement" && parent.init === node) {
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return true;
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}
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node = parent;
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}
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return false;
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};
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if (node.operator === "in" && isLeftOfAForStatement(node)) {
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return true;
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}
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}
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// fallthrough
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case "TSTypeAssertionExpression":
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case "TSAsExpression":
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case "LogicalExpression":
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switch (parent.type) {
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case "CallExpression":
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case "NewExpression":
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return name === "callee" && parent.callee === node;
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case "ClassDeclaration":
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return name === "superClass" && parent.superClass === node;
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case "TSTypeAssertionExpression":
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case "TaggedTemplateExpression":
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case "UnaryExpression":
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case "SpreadElement":
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case "SpreadProperty":
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case "BindExpression":
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case "AwaitExpression":
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case "TSAsExpression":
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case "TSNonNullExpression":
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return true;
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case "MemberExpression":
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return name === "object" && parent.object === node;
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case "BinaryExpression":
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case "LogicalExpression": {
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if (!node.operator && node.type !== "TSTypeAssertionExpression") {
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return true;
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}
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const po = parent.operator;
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const pp = util.getPrecedence(po);
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const no = node.operator;
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const np = util.getPrecedence(no);
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if (pp > np) {
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return true;
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}
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if (po === "||" && no === "&&") {
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return true;
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}
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if (pp === np && name === "right") {
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assert.strictEqual(parent.right, node);
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return true;
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}
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if (pp === np && !util.shouldFlatten(po, no)) {
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return true;
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}
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// Add parenthesis when working with binary operators
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// It's not stricly needed but helps with code understanding
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if (util.isBitwiseOperator(po)) {
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return true;
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}
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return false;
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}
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default:
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return false;
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}
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case "TSParenthesizedType": {
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const grandParent = this.getParentNode(1);
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if (
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(parent.type === "TypeParameter" ||
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parent.type === "VariableDeclarator" ||
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parent.type === "TypeAnnotation" ||
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parent.type === "GenericTypeAnnotation") &&
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(node.typeAnnotation.type === "TypeAnnotation" &&
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node.typeAnnotation.typeAnnotation.type !== "TSFunctionType" &&
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grandParent.type !== "TSTypeOperator")
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) {
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return false;
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}
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// Delegate to inner TSParenthesizedType
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if (node.typeAnnotation.type === "TSParenthesizedType") {
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return false;
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}
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return true;
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}
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case "SequenceExpression":
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switch (parent.type) {
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case "ReturnStatement":
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return false;
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case "ForStatement":
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// Although parentheses wouldn't hurt around sequence
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// expressions in the head of for loops, traditional style
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// dictates that e.g. i++, j++ should not be wrapped with
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// parentheses.
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return false;
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case "ExpressionStatement":
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return name !== "expression";
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case "ArrowFunctionExpression":
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// We do need parentheses, but SequenceExpressions are handled
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// specially when printing bodies of arrow functions.
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return name !== "body";
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default:
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// Otherwise err on the side of overparenthesization, adding
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// explicit exceptions above if this proves overzealous.
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return true;
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}
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case "YieldExpression":
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if (
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parent.type === "UnaryExpression" ||
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parent.type === "AwaitExpression" ||
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parent.type === "TSAsExpression" ||
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parent.type === "TSNonNullExpression"
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) {
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return true;
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}
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// else fallthrough
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case "AwaitExpression":
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switch (parent.type) {
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case "TaggedTemplateExpression":
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case "BinaryExpression":
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case "LogicalExpression":
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case "SpreadElement":
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case "SpreadProperty":
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case "TSAsExpression":
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case "TSNonNullExpression":
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return true;
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case "MemberExpression":
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return parent.object === node;
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case "NewExpression":
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case "CallExpression":
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return parent.callee === node;
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case "ConditionalExpression":
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return parent.test === node;
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default:
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return false;
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}
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case "ArrayTypeAnnotation":
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return parent.type === "NullableTypeAnnotation";
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case "IntersectionTypeAnnotation":
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case "UnionTypeAnnotation":
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return (
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parent.type === "ArrayTypeAnnotation" ||
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parent.type === "NullableTypeAnnotation" ||
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parent.type === "IntersectionTypeAnnotation" ||
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parent.type === "UnionTypeAnnotation"
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);
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case "NullableTypeAnnotation":
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return parent.type === "ArrayTypeAnnotation";
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case "FunctionTypeAnnotation":
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return (
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parent.type === "UnionTypeAnnotation" ||
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parent.type === "IntersectionTypeAnnotation"
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);
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case "StringLiteral":
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case "NumericLiteral":
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case "Literal":
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if (
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typeof node.value === "string" &&
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parent.type === "ExpressionStatement" &&
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// TypeScript workaround for eslint/typescript-eslint-parser#267
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// See corresponding workaround in printer.js case: "Literal"
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((options.parser !== "typescript" && !parent.directive) ||
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(options.parser === "typescript" &&
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options.originalText.substr(util.locStart(node) - 1, 1) === "("))
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) {
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// To avoid becoming a directive
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const grandParent = this.getParentNode(1);
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return (
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grandParent.type === "Program" ||
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grandParent.type === "BlockStatement"
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);
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}
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return (
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parent.type === "MemberExpression" &&
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typeof node.value === "number" &&
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name === "object" &&
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parent.object === node
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);
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case "AssignmentExpression": {
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const grandParent = this.getParentNode(1);
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if (parent.type === "ArrowFunctionExpression" && parent.body === node) {
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return true;
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} else if (
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parent.type === "ClassProperty" &&
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parent.key === node &&
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parent.computed
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) {
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return false;
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} else if (
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parent.type === "TSPropertySignature" &&
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parent.name === node
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) {
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return false;
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} else if (
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parent.type === "ForStatement" &&
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(parent.init === node || parent.update === node)
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) {
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return false;
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} else if (parent.type === "ExpressionStatement") {
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return node.left.type === "ObjectPattern";
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} else if (parent.type === "TSPropertySignature" && parent.key === node) {
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return false;
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} else if (parent.type === "AssignmentExpression") {
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return false;
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} else if (
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parent.type === "SequenceExpression" &&
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grandParent &&
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grandParent.type === "ForStatement" &&
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(grandParent.init === parent || grandParent.update === parent)
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) {
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return false;
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}
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return true;
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}
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case "ConditionalExpression":
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switch (parent.type) {
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case "TaggedTemplateExpression":
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case "UnaryExpression":
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case "SpreadElement":
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case "SpreadProperty":
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case "BinaryExpression":
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case "LogicalExpression":
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case "ExportDefaultDeclaration":
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case "AwaitExpression":
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case "JSXSpreadAttribute":
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case "TSTypeAssertionExpression":
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case "TSAsExpression":
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case "TSNonNullExpression":
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return true;
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case "NewExpression":
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case "CallExpression":
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return name === "callee" && parent.callee === node;
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case "ConditionalExpression":
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return name === "test" && parent.test === node;
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case "MemberExpression":
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return name === "object" && parent.object === node;
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default:
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return false;
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}
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case "FunctionExpression":
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switch (parent.type) {
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case "CallExpression":
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return name === "callee"; // Not strictly necessary, but it's clearer to the reader if IIFEs are wrapped in parentheses.
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case "TaggedTemplateExpression":
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return true; // This is basically a kind of IIFE.
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case "ExportDefaultDeclaration":
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return true;
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default:
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return false;
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}
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case "ArrowFunctionExpression":
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switch (parent.type) {
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case "CallExpression":
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return name === "callee";
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case "NewExpression":
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return name === "callee";
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case "MemberExpression":
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return name === "object";
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case "TSAsExpression":
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case "BindExpression":
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case "TaggedTemplateExpression":
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case "UnaryExpression":
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case "LogicalExpression":
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case "BinaryExpression":
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case "AwaitExpression":
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case "TSTypeAssertionExpression":
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return true;
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case "ConditionalExpression":
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return name === "test";
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default:
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return false;
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}
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case "ClassExpression":
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return parent.type === "ExportDefaultDeclaration";
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}
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return false;
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};
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function isStatement(node) {
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return (
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node.type === "BlockStatement" ||
|
|
node.type === "BreakStatement" ||
|
|
node.type === "ClassBody" ||
|
|
node.type === "ClassDeclaration" ||
|
|
node.type === "ClassMethod" ||
|
|
node.type === "ClassProperty" ||
|
|
node.type === "ContinueStatement" ||
|
|
node.type === "DebuggerStatement" ||
|
|
node.type === "DeclareClass" ||
|
|
node.type === "DeclareExportAllDeclaration" ||
|
|
node.type === "DeclareExportDeclaration" ||
|
|
node.type === "DeclareFunction" ||
|
|
node.type === "DeclareInterface" ||
|
|
node.type === "DeclareModule" ||
|
|
node.type === "DeclareModuleExports" ||
|
|
node.type === "DeclareVariable" ||
|
|
node.type === "DoWhileStatement" ||
|
|
node.type === "ExportAllDeclaration" ||
|
|
node.type === "ExportDefaultDeclaration" ||
|
|
node.type === "ExportNamedDeclaration" ||
|
|
node.type === "ExpressionStatement" ||
|
|
node.type === "ForAwaitStatement" ||
|
|
node.type === "ForInStatement" ||
|
|
node.type === "ForOfStatement" ||
|
|
node.type === "ForStatement" ||
|
|
node.type === "FunctionDeclaration" ||
|
|
node.type === "IfStatement" ||
|
|
node.type === "ImportDeclaration" ||
|
|
node.type === "InterfaceDeclaration" ||
|
|
node.type === "LabeledStatement" ||
|
|
node.type === "MethodDefinition" ||
|
|
node.type === "ReturnStatement" ||
|
|
node.type === "SwitchStatement" ||
|
|
node.type === "ThrowStatement" ||
|
|
node.type === "TryStatement" ||
|
|
node.type === "TSAbstractClassDeclaration" ||
|
|
node.type === "TSEnumDeclaration" ||
|
|
node.type === "TSImportEqualsDeclaration" ||
|
|
node.type === "TSInterfaceDeclaration" ||
|
|
node.type === "TSModuleDeclaration" ||
|
|
node.type === "TSNamespaceExportDeclaration" ||
|
|
node.type === "TSNamespaceFunctionDeclaration" ||
|
|
node.type === "TypeAlias" ||
|
|
node.type === "VariableDeclaration" ||
|
|
node.type === "WhileStatement" ||
|
|
node.type === "WithStatement"
|
|
);
|
|
}
|
|
|
|
module.exports = FastPath;
|