Do not format template literals (#749)

src/doc-utils.js

@@ -33,6 +33,23 @@ function traverseDoc(doc, onEnter, onExit) {
   traverseDocRec(doc);
 }
 
+function mapDoc(doc, func) {
+  doc = func(doc);
+
+  if(doc.type === "concat") {
+    return Object.assign({}, doc, { parts: doc.parts.map(d => mapDoc(d, func)) });
+  } else if (doc.type === "if-break") {
+    return Object.assign({}, doc, {
+      breakContents: doc.breakContents && mapDoc(doc.breakContents, func),
+      flatContents: doc.flatContents && mapDoc(doc.flatContents, func)
+    });
+  } else if(doc.contents) {
+    return Object.assign({}, doc, { contents: mapDoc(doc.contents, func) });
+  } else {
+    return doc;
+  }
+}
+
 function findInDoc(doc, fn, defaultValue) {
   var result = defaultValue;
   traverseDoc(doc, function(doc) {
@@ -132,5 +149,6 @@ module.exports = {
   willBreak,
   isLineNext,
   traverseDoc,
+  mapDoc,
   propagateBreaks
 };

src/printer.js

@@ -1365,6 +1365,19 @@ function genericPrintNoParens(path, options, print) {
     case "TemplateLiteral":
       var expressions = path.map(print, "expressions");
 
+      function removeLines(doc) {
+        // Force this doc into flat mode by statically converting all
+        // lines into spaces (or soft lines into nothing). Hard lines
+        // should still output because there's too great of a chance
+        // of breaking existing assumptions otherwise.
+        return docUtils.mapDoc(doc, d => {
+          if (d.type === "line" && !d.hard) {
+            return d.soft ? "" : " ";
+          }
+          return d;
+        });
+      }
+
       parts.push("`");
 
       path.each(
@@ -1374,7 +1387,7 @@ function genericPrintNoParens(path, options, print) {
           parts.push(print(childPath));
 
           if (i < expressions.length) {
-            parts.push("${", expressions[i], "}");
+            parts.push("${", removeLines(expressions[i]), "}");
           }
         },
         "quasis"

tests/strings/__snapshots__/jsfmt.spec.js.snap

@@ -26,6 +26,16 @@ exports[`strings.js 1`] = `
 
   '\\\\uD801\\\\uDC28',
 ];
+
+foo(\`a long string \${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 } with expr\`);
+
+const x = \`a long string \${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + ( function() {return 3 })() + 3 + 2 + 3 + 2 + 3 } with expr\`;
+
+foo(\`a long string \${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + ( function() {
+  const x = 5;
+
+  return x;
+ })() + 3 + 2 + 3 + 2 + 3 } with expr\`);
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 [
   \\"abc\\",
@@ -51,5 +61,17 @@ exports[`strings.js 1`] = `
   \\"🐶\\",
   '\\\\uD801\\\\uDC28'
 ];
+foo(
+  \`a long string \${1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3} with expr\`
+);
+const x = \`a long string \${1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + (function() {
+    return 3;
+  })() + 3 + 2 + 3 + 2 + 3} with expr\`;
+foo(
+  \`a long string \${1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + (function() {
+      const x = 5;
+      return x;
+    })() + 3 + 2 + 3 + 2 + 3} with expr\`
+);
 "
 `;

tests/strings/strings.js

@@ -23,3 +23,13 @@
 
   '\uD801\uDC28',
 ];
+
+foo(`a long string ${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 } with expr`);
+
+const x = `a long string ${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + ( function() {return 3 })() + 3 + 2 + 3 + 2 + 3 } with expr`;
+
+foo(`a long string ${ 1 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + 3 + 2 + ( function() {
+  const x = 5;
+
+  return x;
+ })() + 3 + 2 + 3 + 2 + 3 } with expr`);