fix: #3073 function format not escaping control characters and doub…

…le quotes in strings

src/utils/string.js

@@ -86,7 +86,7 @@ function _format (value, options) {
   }
 
   if (isString(value)) {
-    return '"' + value + '"'
+    return stringify(value)
   }
 
   if (typeof value === 'function') {
@@ -101,7 +101,7 @@ function _format (value, options) {
       return value.toString(options)
     } else {
       const entries = Object.keys(value).map(key => {
-        return '"' + key + '": ' + format(value[key], options)
+        return stringify(key) + ': ' + format(value[key], options)
       })
 
       return '{' + entries.join(', ') + '}'
@@ -122,28 +122,24 @@ export function stringify (value) {
   let escaped = ''
   let i = 0
   while (i < text.length) {
-    let c = text.charAt(i)
-
-    if (c === '\\') {
-      escaped += c
-      i++
-
-      c = text.charAt(i)
-      if (c === '' || '"\\/bfnrtu'.indexOf(c) === -1) {
-        escaped += '\\' // no valid escape character -> escape it
-      }
-      escaped += c
-    } else if (c === '"') {
-      escaped += '\\"'
-    } else {
-      escaped += c
-    }
+    const c = text.charAt(i)
+    escaped += (c in controlCharacters) ? controlCharacters[c] : c
     i++
   }
 
   return '"' + escaped + '"'
 }
 
+const controlCharacters = {
+  '"': '\\"',
+  '\\': '\\\\',
+  '\b': '\\b',
+  '\f': '\\f',
+  '\n': '\\n',
+  '\r': '\\r',
+  '\t': '\\t'
+}
+
 /**
  * Escape special HTML characters
  * @param {*} value

test/unit-tests/expression/node/ConstantNode.test.js

@@ -138,6 +138,7 @@ describe('ConstantNode', function () {
     assert.deepStrictEqual(new ConstantNode(math.bignumber('1e500')).toString(), '1e+500')
     assert.deepStrictEqual(new ConstantNode(math.fraction(2, 3)).toString(), '2/3')
     assert.strictEqual(new ConstantNode('hi').toString(), '"hi"')
+    assert.strictEqual(new ConstantNode('with " double quote').toString(), '"with \\" double quote"')
     assert.strictEqual(new ConstantNode(true).toString(), 'true')
     assert.strictEqual(new ConstantNode(false).toString(), 'false')
     assert.strictEqual(new ConstantNode(undefined).toString(), 'undefined')
@@ -218,6 +219,6 @@ describe('ConstantNode', function () {
   it('should escape strings in toTex', function () {
     const n = new ConstantNode('space tab\tunderscore_bla$/')
 
-    assert.strictEqual(n.toTex(), '\\mathtt{"space~tab\\qquad{}underscore\\_bla\\$/"}')
+    assert.strictEqual(n.toTex(), '\\mathtt{"space~tab\\textbackslash{}tunderscore\\_bla\\$/"}')
   })
 })

test/unit-tests/utils/string.test.js

@@ -71,6 +71,11 @@ describe('string', function () {
       assert.strictEqual(format('string'), '"string"')
     })
 
+    it('should format a string with escape characters', function () {
+      assert.strictEqual(format('with " double quote'), '"with \\" double quote"')
+      assert.strictEqual(format('with \\ backslash'), '"with \\\\ backslash"')
+    })
+
     it('should format an object', function () {
       const obj = {
         a: 1.1111,
@@ -81,6 +86,11 @@ describe('string', function () {
       assert.strictEqual(format(obj, 3), '{"a": 1.11, "b": 2.22 + 3i}')
     })
 
+    it('should format an object with escape characters', function () {
+      assert.strictEqual(format({ 'with " double quote': 42 }), '{"with \\" double quote": 42}')
+      assert.strictEqual(format({ 'with \\ backslash': 42 }), '{"with \\\\ backslash": 42}')
+    })
+
     it('should format an object with its own format function', function () {
       const obj = {
         format: function (options) {