From 09ac476a32f94016831366ed7135eb8b3b57d592 Mon Sep 17 00:00:00 2001
From: Adam Pearce <1wheel@gmail.com>
Date: Tue, 24 Apr 2018 06:54:45 -0400
Subject: [PATCH] Nicer line wrapping for d3 (#4285)

* d3 counts as a constructor

* adds test

* Tweak wording

* docs: fix linting

* updates test

* no $ special case

* renames function

* shorter function name

* removes trailing white space
---
 src/language-js/printer-estree.js             | 14 ++++++------
 .../comments/__snapshots__/jsfmt.spec.js.snap |  4 ++--
 tests/comments/return-statement.js            |  2 +-
 .../__snapshots__/jsfmt.spec.js.snap          | 22 +++++++++++++++++++
 tests/method-chain/d3.js                      |  9 ++++++++
 5 files changed, 41 insertions(+), 10 deletions(-)
 create mode 100644 tests/method-chain/d3.js

diff --git a/src/language-js/printer-estree.js b/src/language-js/printer-estree.js
index f973e426..63eae5ed 100644
--- a/src/language-js/printer-estree.js
+++ b/src/language-js/printer-estree.js
@@ -4141,11 +4141,11 @@ function printMemberChain(path, options, print) {
   //     .map(x => x)
   //
   // In order to detect those cases, we use an heuristic: if the first
-  // node is just an identifier with the name starting with a capital
-  // letter, just a sequence of _$ or this. The rationale is that they are
-  // likely to be factories.
-  function isFactory(name) {
-    return name.match(/(^[A-Z])|^[_$]+$/);
+  // node is an identifier with the name starting with a capital letter,
+  // or shorter than tabWidth. The rationale is that they are likely
+  // to be factories.
+  function isNoWrap(name) {
+    return name.match(/(^[A-Z])/) || name.length <= options.tabWidth;
   }
   const shouldMerge =
     groups.length >= 2 &&
@@ -4153,12 +4153,12 @@ function printMemberChain(path, options, print) {
     ((groups[0].length === 1 &&
       (groups[0][0].node.type === "ThisExpression" ||
         (groups[0][0].node.type === "Identifier" &&
-          (isFactory(groups[0][0].node.name) ||
+          (isNoWrap(groups[0][0].node.name) ||
             (groups[1].length && groups[1][0].node.computed))))) ||
       (groups[0].length > 1 &&
         groups[0][groups[0].length - 1].node.type === "MemberExpression" &&
         groups[0][groups[0].length - 1].node.property.type === "Identifier" &&
-        (isFactory(groups[0][groups[0].length - 1].node.property.name) ||
+        (isNoWrap(groups[0][groups[0].length - 1].node.property.name) ||
           (groups[1].length && groups[1][0].node.computed))));
 
   function printGroup(printedGroup) {
diff --git a/tests/comments/__snapshots__/jsfmt.spec.js.snap b/tests/comments/__snapshots__/jsfmt.spec.js.snap
index 0757ebef..ccf9db93 100644
--- a/tests/comments/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/comments/__snapshots__/jsfmt.spec.js.snap
@@ -1341,7 +1341,7 @@ function memberOutside() {
 function memberInAndOutWithCalls() {
   return (
     // Reason for a
-    a.b()
+    aFunction.b()
   ).c.d()
 }
 
@@ -1469,7 +1469,7 @@ function memberOutside() {
 
 function memberInAndOutWithCalls() {
   return (
-    a
+    aFunction
       .b// Reason for a
       ()
       .c.d()
diff --git a/tests/comments/return-statement.js b/tests/comments/return-statement.js
index 838e079e..4953d6b7 100644
--- a/tests/comments/return-statement.js
+++ b/tests/comments/return-statement.js
@@ -82,7 +82,7 @@ function memberOutside() {
 function memberInAndOutWithCalls() {
   return (
     // Reason for a
-    a.b()
+    aFunction.b()
   ).c.d()
 }
 
diff --git a/tests/method-chain/__snapshots__/jsfmt.spec.js.snap b/tests/method-chain/__snapshots__/jsfmt.spec.js.snap
index 29f54015..f9d26340 100644
--- a/tests/method-chain/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/method-chain/__snapshots__/jsfmt.spec.js.snap
@@ -485,6 +485,28 @@ object[
 
 `;
 
+exports[`d3.js 1`] = `
+d3.select('body')
+  .append('circle')
+  .at({ width: 30, fill: '#f0f' })
+  .st({ fontWeight: 600 })
+
+d3.scaleLinear()
+  .domain([1950, 1980])
+  .range([0, width])
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+d3.select("body")
+  .append("circle")
+  .at({ width: 30, fill: "#f0f" })
+  .st({ fontWeight: 600 });
+
+d3.scaleLinear()
+  .domain([1950, 1980])
+  .range([0, width]);
+
+`;
+
 exports[`first_long.js 1`] = `
 export default function theFunction(action$, store) {
   return action$.ofType(THE_ACTION).switchMap(action => Observable
diff --git a/tests/method-chain/d3.js b/tests/method-chain/d3.js
new file mode 100644
index 00000000..5912bb74
--- /dev/null
+++ b/tests/method-chain/d3.js
@@ -0,0 +1,9 @@
+d3.select('body')
+  .append('circle')
+  .at({ width: 30, fill: '#f0f' })
+  .st({ fontWeight: 600 })
+
+d3.scaleLinear()
+  .domain([1950, 1980])
+  .range([0, width])
+