From 04e4ef375844b011ab586072ecc97678afe838b4 Mon Sep 17 00:00:00 2001
From: Sidharth Vinod <sidharthv96@gmail.com>
Date: Sun, 5 Apr 2020 16:21:29 +0530
Subject: [PATCH] Uniform line endings for multi line strings/comments (#7891)

---
 changelog_unreleased/javascript/pr-7891.md    |  42 +++++
 src/document/doc-printer.js                   |   9 +-
 src/main/core.js                              |  13 +-
 .../__snapshots__/jsfmt.spec.js.snap          | 177 ++++++++++++++++++
 tests/end_of_line/multiline.js                |  23 +++
 5 files changed, 249 insertions(+), 15 deletions(-)
 create mode 100644 changelog_unreleased/javascript/pr-7891.md
 create mode 100644 tests/end_of_line/multiline.js

diff --git a/changelog_unreleased/javascript/pr-7891.md b/changelog_unreleased/javascript/pr-7891.md
new file mode 100644
index 000000000000..75a7a2e1da6e
--- /dev/null
+++ b/changelog_unreleased/javascript/pr-7891.md
@@ -0,0 +1,42 @@
+#### Fix: line endings were not always converted properly in multiline strings and comments ([#7891](https://github.com/prettier/prettier/pull/7891) by [@sidharthv96](https://github.com/sidharthv96))
+
+<!-- prettier-ignore -->
+```
+// Input
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<CRLF>
+  (_0: IAmIncredibleLongParameterType) => {<CRLF>
+    setTimeout(() => {<CRLF>
+      /*<CRLF>
+        Multiline comment<CRLF>
+        Multiline comment<CRLF>
+        Multiline comment<CRLF>
+      */<CRLF>
+      console.log(<CRLF>
+        "Multiline string\<CRLF>
+         Multiline string\<CRLF>
+         Multiline string"<CRLF>
+      );<CRLF>
+    });<CRLF>
+  }<CRLF>
+);<CRLF>
+
+// Prettier stable
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<CRLF>
+  (_0: IAmIncredibleLongParameterType) => {<CRLF>
+    setTimeout(() => {<CRLF>
+      /*<LF>
+        Multiline comment<LF>
+        Multiline comment<LF>
+        Multiline comment<LF>
+      */<CRLF>
+      console.log(<CRLF>
+        "Multiline string\<LF>
+         Multiline string\<LF>
+         Multiline string"<CRLF>
+      );<CRLF>
+    });<CRLF>
+  }<CRLF>
+);<CRLF>
+
+// Prettier master: same as input
+```
diff --git a/src/document/doc-printer.js b/src/document/doc-printer.js
index 800e44e1c4a3..737532fb3af5 100644
--- a/src/document/doc-printer.js
+++ b/src/document/doc-printer.js
@@ -253,9 +253,12 @@ function printDocToString(doc, options) {
     const [ind, mode, doc] = cmds.pop();
 
     if (typeof doc === "string") {
-      out.push(doc);
-
-      pos += getStringWidth(doc);
+      const formatted =
+        newLine !== "\n" && doc.includes("\n")
+          ? doc.replace(/\n/g, newLine)
+          : doc;
+      out.push(formatted);
+      pos += getStringWidth(formatted);
     } else {
       switch (doc.type) {
         case "cursor":
diff --git a/src/main/core.js b/src/main/core.js
index 8d35eab40673..58ff4fa31a0d 100644
--- a/src/main/core.js
+++ b/src/main/core.js
@@ -14,7 +14,6 @@ const {
 const rangeUtil = require("./range-util");
 const privateUtil = require("../common/util");
 const {
-  utils: { mapDoc },
   printer: { printDocToString },
   debug: { printDocToDebug },
 } = require("../document");
@@ -85,17 +84,7 @@ function coreFormat(text, opts, addAlignmentSize) {
   const astComments = attachComments(text, ast, opts);
   const doc = printAstToDoc(ast, opts, addAlignmentSize);
 
-  const eol = convertEndOfLineToChars(opts.endOfLine);
-  const result = printDocToString(
-    opts.endOfLine === "lf"
-      ? doc
-      : mapDoc(doc, (currentDoc) =>
-          typeof currentDoc === "string" && currentDoc.includes("\n")
-            ? currentDoc.replace(/\n/g, eol)
-            : currentDoc
-        ),
-    opts
-  );
+  const result = printDocToString(doc, opts);
 
   ensureAllCommentsPrinted(astComments);
   // Remove extra leading indentation as well as the added indentation after last newline
diff --git a/tests/end_of_line/__snapshots__/jsfmt.spec.js.snap b/tests/end_of_line/__snapshots__/jsfmt.spec.js.snap
index b5dcc9ee3430..6212d4daf4d8 100644
--- a/tests/end_of_line/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/end_of_line/__snapshots__/jsfmt.spec.js.snap
@@ -56,3 +56,180 @@ function f() {<CRLF>
 
 ================================================================================
 `;
+
+exports[`multiline.js 1`] = `
+====================================options=====================================
+endOfLine: "lf"
+parsers: ["babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+type IAmIncredibleLongParameterType = {};<LF>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<LF>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<LF>
+  (_0: IAmIncredibleLongParameterType) => {<LF>
+    setTimeout(() => {<LF>
+      /*<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+      */<LF>
+      console.log(<LF>
+        'Multiline string\\<LF>
+         Multiline string\\<LF>
+         Multiline string'<LF>
+      );<LF>
+      console.log(<LF>
+        \`Multiline \\n string\\<LF>
+         Multiline string\\<LF>
+         Multiline string\`<LF>
+      );<LF>
+    });<LF>
+  }<LF>
+);<LF>
+
+=====================================output=====================================
+type IAmIncredibleLongParameterType = {};<LF>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<LF>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<LF>
+  (_0: IAmIncredibleLongParameterType) => {<LF>
+    setTimeout(() => {<LF>
+      /*<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+      */<LF>
+      console.log(<LF>
+        "Multiline string\\<LF>
+         Multiline string\\<LF>
+         Multiline string"<LF>
+      );<LF>
+      console.log(<LF>
+        \`Multiline \\n string\\<LF>
+         Multiline string\\<LF>
+         Multiline string\`<LF>
+      );<LF>
+    });<LF>
+  }<LF>
+);<LF>
+
+================================================================================
+`;
+
+exports[`multiline.js 2`] = `
+====================================options=====================================
+endOfLine: "cr"
+parsers: ["babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+type IAmIncredibleLongParameterType = {};<LF>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<LF>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<LF>
+  (_0: IAmIncredibleLongParameterType) => {<LF>
+    setTimeout(() => {<LF>
+      /*<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+      */<LF>
+      console.log(<LF>
+        'Multiline string\\<LF>
+         Multiline string\\<LF>
+         Multiline string'<LF>
+      );<LF>
+      console.log(<LF>
+        \`Multiline \\n string\\<LF>
+         Multiline string\\<LF>
+         Multiline string\`<LF>
+      );<LF>
+    });<LF>
+  }<LF>
+);<LF>
+
+=====================================output=====================================
+type IAmIncredibleLongParameterType = {};<CR>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<CR>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<CR>
+  (_0: IAmIncredibleLongParameterType) => {<CR>
+    setTimeout(() => {<CR>
+      /*<CR>
+          Multiline comment<CR>
+          Multiline comment<CR>
+          Multiline comment<CR>
+      */<CR>
+      console.log(<CR>
+        "Multiline string\\<CR>
+         Multiline string\\<CR>
+         Multiline string"<CR>
+      );<CR>
+      console.log(<CR>
+        \`Multiline \\n string\\<CR>
+         Multiline string\\<CR>
+         Multiline string\`<CR>
+      );<CR>
+    });<CR>
+  }<CR>
+);<CR>
+
+================================================================================
+`;
+
+exports[`multiline.js 3`] = `
+====================================options=====================================
+endOfLine: "crlf"
+parsers: ["babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+type IAmIncredibleLongParameterType = {};<LF>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<LF>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<LF>
+  (_0: IAmIncredibleLongParameterType) => {<LF>
+    setTimeout(() => {<LF>
+      /*<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+          Multiline comment<LF>
+      */<LF>
+      console.log(<LF>
+        'Multiline string\\<LF>
+         Multiline string\\<LF>
+         Multiline string'<LF>
+      );<LF>
+      console.log(<LF>
+        \`Multiline \\n string\\<LF>
+         Multiline string\\<LF>
+         Multiline string\`<LF>
+      );<LF>
+    });<LF>
+  }<LF>
+);<LF>
+
+=====================================output=====================================
+type IAmIncredibleLongParameterType = {};<CRLF>
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};<CRLF>
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(<CRLF>
+  (_0: IAmIncredibleLongParameterType) => {<CRLF>
+    setTimeout(() => {<CRLF>
+      /*<CRLF>
+          Multiline comment<CRLF>
+          Multiline comment<CRLF>
+          Multiline comment<CRLF>
+      */<CRLF>
+      console.log(<CRLF>
+        "Multiline string\\<CRLF>
+         Multiline string\\<CRLF>
+         Multiline string"<CRLF>
+      );<CRLF>
+      console.log(<CRLF>
+        \`Multiline \\n string\\<CRLF>
+         Multiline string\\<CRLF>
+         Multiline string\`<CRLF>
+      );<CRLF>
+    });<CRLF>
+  }<CRLF>
+);<CRLF>
+
+================================================================================
+`;
diff --git a/tests/end_of_line/multiline.js b/tests/end_of_line/multiline.js
new file mode 100644
index 000000000000..b51866579807
--- /dev/null
+++ b/tests/end_of_line/multiline.js
@@ -0,0 +1,23 @@
+type IAmIncredibleLongParameterType = {};
+const IAmAnotherFunctionName = (_0: IAmIncredibleLongParameterType) => {};
+export const IAmIncredibleLongFunctionName = IAmAnotherFunctionName(
+  (_0: IAmIncredibleLongParameterType) => {
+    setTimeout(() => {
+      /*
+          Multiline comment
+          Multiline comment
+          Multiline comment
+      */
+      console.log(
+        'Multiline string\
+         Multiline string\
+         Multiline string'
+      );
+      console.log(
+        `Multiline \n string\
+         Multiline string\
+         Multiline string`
+      );
+    });
+  }
+);