1st try to fix issue nodeca#587

lib/js-yaml/dumper.js

@@ -280,24 +280,25 @@ function chooseScalarStyle(string, singleLineOnly, indentPerLevel, lineWidth, te
   var hasFoldableLine = false; // only checked if shouldTrackWidth
   var shouldTrackWidth = lineWidth !== -1;
   var previousLineBreak = -1; // count the first line correctly
-  var plain = isPlainSafeFirst(string.charCodeAt(0))
-          && !isWhitespace(string.charCodeAt(string.length - 1));
+  var plain = isPlainSafeFirst(string.codePointAt(0))
+          && !isWhitespace(string.codePointAt(string.length - 1));
 
+  var chars = Array.from(string);
   if (singleLineOnly) {
     // Case: no block styles.
     // Check for disallowed characters to rule out plain and single.
-    for (i = 0; i < string.length; i++) {
-      char = string.charCodeAt(i);
+    for (i = 0; i < chars.length; i++) {
+      char = chars[i].codePointAt(0);
       if (!isPrintable(char)) {
         return STYLE_DOUBLE;
       }
-      prev_char = i > 0 ? string.charCodeAt(i - 1) : null;
+      prev_char = i > 0 ? chars[i - 1].codePointAt(0) : null;
       plain = plain && isPlainSafe(char, prev_char);
     }
   } else {
     // Case: block styles permitted.
-    for (i = 0; i < string.length; i++) {
-      char = string.charCodeAt(i);
+    for (i = 0; i < chars.length; i++) {
+      char = chars[i].codePointAt(0);
       if (char === CHAR_LINE_FEED) {
         hasLineBreak = true;
         // Check if any line can be folded.
@@ -311,7 +312,7 @@ function chooseScalarStyle(string, singleLineOnly, indentPerLevel, lineWidth, te
       } else if (!isPrintable(char)) {
         return STYLE_DOUBLE;
       }
-      prev_char = i > 0 ? string.charCodeAt(i - 1) : null;
+      prev_char = i > 0 ? chars[i - 1].codePointAt(0) : null;
       plain = plain && isPlainSafe(char, prev_char);
     }
     // in case the end is missing a \n
@@ -489,24 +490,15 @@ function foldLine(line, width) {
 // Escapes a double-quoted string.
 function escapeString(string) {
   var result = '';
-  var char, nextChar;
+  var char;
   var escapeSeq;
 
-  for (var i = 0; i < string.length; i++) {
-    char = string.charCodeAt(i);
-    // Check for surrogate pairs (reference Unicode 3.0 section "3.7 Surrogates").
-    if (char >= 0xD800 && char <= 0xDBFF/* high surrogate */) {
-      nextChar = string.charCodeAt(i + 1);
-      if (nextChar >= 0xDC00 && nextChar <= 0xDFFF/* low surrogate */) {
-        // Combine the surrogate pair and store it escaped.
-        result += encodeHex((char - 0xD800) * 0x400 + nextChar - 0xDC00 + 0x10000);
-        // Advance index one extra since we already used that char here.
-        i++; continue;
-      }
-    }
+  var chars = Array.from(string);
+  for (var i = 0; i < chars.length; i++) {
+    char = chars[i].codePointAt(0);
     escapeSeq = ESCAPE_SEQUENCES[char];
     result += !escapeSeq && isPrintable(char)
-      ? string[i]
+      ? chars[i]
       : escapeSeq || encodeHex(char);
   }
 

test/issues/0587.js

@@ -0,0 +1,20 @@
+'use strict';
+
+
+var assert = require('assert');
+var yaml = require('../../');
+
+
+suite('Should not escape emojis', function () {
+  test('plain', function () {
+    assert.strictEqual(yaml.safeDump('😀'), '😀\n');
+  });
+
+  test('escape \\ and " in double-quoted', function () {
+    assert.strictEqual(yaml.safeDump('\u0007 😀 escape\\ escaper"'), '"\\a 😀 escape\\\\ escaper\\""\n');
+  });
+
+  test('load', function () {
+    assert.strictEqual(yaml.safeLoad('"\\U0001F600"'), '😀');
+  });
+});