Support JSON6 (#10456)

* Add test

* Support JSON6

* Test

* Print `null` instead of holes

* More tests

* Update changelog

* Style

* Minor refactor

* Fix AST clean

* Fix `Identifier` clean

* Fix AST compare

* Style

* Reword changelog

Co-authored-by: Georgii Dolzhykov <thorn.mailbox@gmail.com>

changelog_unreleased/json/10346.md

@@ -1,6 +1,6 @@
-#### Stricter JSON parser (#10346, #10443 by @fisker)
+#### Stricter JSON parser (#10346, #10443, #10456 by @fisker)
 
-Previously we allow all kinds of JavaScript expressions in `json` and `json5` parser, now they are stricter.
+Prettier internally uses a JavaScript expression parser to parse JSON. That's why the `json` and `json5` parsers used to be very forgiving and allowed all kinds of JavaScript expressions. Now they are much stricter, although some simple non-standard syntax is still allowed (e.g., [JSON6](https://github.com/d3x0r/JSON6) is supported, except for multiple minus signs: `----123`).
 
 <!-- prettier-ignore -->
 ```js

src/language-js/parser/json.js

@@ -45,11 +45,9 @@ function assertJsonNode(node) {
   switch (node.type) {
     case "ArrayExpression":
       for (const element of node.elements) {
-        if (element === null) {
-          throw createJsonError(node, "Sparse array");
+        if (element !== null) {
+          assertJsonNode(element);
         }
-
-        assertJsonNode(element);
       }
 
       return;
@@ -84,16 +82,35 @@ function assertJsonNode(node) {
 
       return;
     case "Identifier":
-      // JSON5 https://spec.json5.org/#numbers
-      if (node.name !== "Infinity" && node.name !== "NaN") {
+      if (
+        // JSON5 https://spec.json5.org/#numbers
+        node.name !== "Infinity" &&
+        node.name !== "NaN" &&
+        // JSON6 https://github.com/d3x0r/JSON6
+        node.name !== "undefined"
+      ) {
         throw createJsonError(node, `Identifier '${node.name}'`);
       }
 
+      return;
+    case "TemplateLiteral":
+      if (isNonEmptyArray(node.expressions)) {
+        throw createJsonError(
+          node.expressions[0],
+          "'TemplateLiteral' with expression"
+        );
+      }
+
+      for (const element of node.quasis) {
+        assertJsonNode(element);
+      }
+
       return;
     case "NullLiteral":
     case "BooleanLiteral":
     case "NumericLiteral":
     case "StringLiteral":
+    case "TemplateElement":
       return;
     default:
       throw createJsonError(node, `'${node.type}'`);

src/language-js/printer-estree-json.js

@@ -10,18 +10,24 @@ function genericPrint(path, options, print) {
   switch (node.type) {
     case "JsonRoot":
       return [path.call(print, "node"), hardline];
-    case "ArrayExpression":
-      return node.elements.length === 0
-        ? "[]"
-        : [
-            "[",
-            indent([
-              hardline,
-              join([",", hardline], path.map(print, "elements")),
-            ]),
-            hardline,
-            "]",
-          ];
+    case "ArrayExpression": {
+      if (node.elements.length === 0) {
+        return "[]";
+      }
+
+      const printed = path.map(
+        (elementPath) =>
+          path.getValue() === null ? "null" : print(elementPath),
+        "elements"
+      );
+
+      return [
+        "[",
+        indent([hardline, join([",", hardline], printed)]),
+        hardline,
+        "]",
+      ];
+    }
     case "ObjectExpression":
       return node.properties.length === 0
         ? "{}"
@@ -55,6 +61,11 @@ function genericPrint(path, options, print) {
       }
       return node.name;
     }
+    case "TemplateLiteral":
+      // There is only one `TemplateElement`
+      return path.call(print, "quasis", 0);
+    case "TemplateElement":
+      return JSON.stringify(node.value.cooked);
     default:
       /* istanbul ignore next */
       throw new Error("unknown type: " + JSON.stringify(node.type));
@@ -67,18 +78,36 @@ const ignoredProperties = new Set([
   "extra",
   "loc",
   "comments",
+  "leadingComments",
+  "trailingComments",
+  "innerComments",
   "errors",
   "range",
 ]);
 
 function clean(node, newNode /*, parent*/) {
   const { type } = node;
-  if (type === "Identifier") {
-    return { type: "StringLiteral", value: node.name };
+  // We print quoted key
+  if (type === "ObjectProperty" && node.key.type === "Identifier") {
+    newNode.key = { type: "StringLiteral", value: node.key.name };
+    return;
   }
   if (type === "UnaryExpression" && node.operator === "+") {
     return newNode.argument;
   }
+  // We print holes in array as `null`
+  if (type === "ArrayExpression") {
+    for (const [index, element] of node.elements.entries()) {
+      if (element === null) {
+        newNode.elements.splice(index, 0, { type: "NullLiteral" });
+      }
+    }
+    return;
+  }
+  // We print `TemplateLiteral` as string
+  if (type === "TemplateLiteral") {
+    return { type: "StringLiteral", value: node.quasis[0].value.cooked };
+  }
 }
 
 clean.ignoredProperties = ignoredProperties;

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

@@ -505,6 +505,474 @@ No \\\\n's!",
 ================================================================================
 `;
 
+exports[`json6.json - {"trailingComma":"all"} format 1`] = `
+====================================options=====================================
+parsers: ["json"]
+printWidth: 80
+trailingComma: "all"
+                                                                                | printWidth
+=====================================input======================================
+[
+{'//': 'Keyword \`undefined\`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      {'as-object-value': \`foo\`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\\0', '\\xFF', '\\u00FF', \`\\u{1F409}\`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]
+
+=====================================output=====================================
+[
+  {
+    "//": "Keyword \`undefined\`",
+    "data": [{ "undefined": undefined }, undefined, [undefined]]
+  },
+
+  {
+    "//": "back-tick quoted strings",
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      { "as-object-value": \`foo\` }
+    ]
+  },
+
+  { "//": "String escapes ", "data": ["\\0", "\\xFF", "\\u00FF", \`\\u{1F409}\`] },
+
+  {
+    "//": "Numbers",
+    "data": [0o123, 0b101010, 1e5, 123_456, 0xdeed_beef, 0123, -Infinity, -NaN]
+  },
+
+  { "//": "empty members", "data": [[,], [1, , 2, , , ,], [1, , 2], [1, , 2]] }
+]
+
+================================================================================
+`;
+
+exports[`json6.json - {"trailingComma":"all"} format 2`] = `
+====================================options=====================================
+parsers: ["json5"]
+printWidth: 80
+trailingComma: "all"
+                                                                                | printWidth
+=====================================input======================================
+[
+{'//': 'Keyword \`undefined\`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      {'as-object-value': \`foo\`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\\0', '\\xFF', '\\u00FF', \`\\u{1F409}\`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]
+
+=====================================output=====================================
+[
+  {
+    "//": "Keyword \`undefined\`",
+    data: [{ undefined: undefined }, undefined, [undefined]],
+  },
+
+  {
+    "//": "back-tick quoted strings",
+    data: [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      { "as-object-value": \`foo\` },
+    ],
+  },
+
+  { "//": "String escapes ", data: ["\\0", "\\xFF", "\\u00FF", \`\\u{1F409}\`] },
+
+  {
+    "//": "Numbers",
+    data: [0o123, 0b101010, 1e5, 123_456, 0xdeed_beef, 0123, -Infinity, -NaN],
+  },
+
+  { "//": "empty members", data: [[,], [1, , 2, , , ,], [1, , 2], [1, , 2]] },
+]
+
+================================================================================
+`;
+
+exports[`json6.json format 1`] = `
+====================================options=====================================
+parsers: ["json"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+[
+{'//': 'Keyword \`undefined\`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      {'as-object-value': \`foo\`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\\0', '\\xFF', '\\u00FF', \`\\u{1F409}\`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]
+
+=====================================output=====================================
+[
+  {
+    "//": "Keyword \`undefined\`",
+    "data": [{ "undefined": undefined }, undefined, [undefined]]
+  },
+
+  {
+    "//": "back-tick quoted strings",
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      { "as-object-value": \`foo\` }
+    ]
+  },
+
+  { "//": "String escapes ", "data": ["\\0", "\\xFF", "\\u00FF", \`\\u{1F409}\`] },
+
+  {
+    "//": "Numbers",
+    "data": [0o123, 0b101010, 1e5, 123_456, 0xdeed_beef, 0123, -Infinity, -NaN]
+  },
+
+  { "//": "empty members", "data": [[,], [1, , 2, , , ,], [1, , 2], [1, , 2]] }
+]
+
+================================================================================
+`;
+
+exports[`json6.json format 2`] = `
+====================================options=====================================
+parsers: ["json5"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+[
+{'//': 'Keyword \`undefined\`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      {'as-object-value': \`foo\`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\\0', '\\xFF', '\\u00FF', \`\\u{1F409}\`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]
+
+=====================================output=====================================
+[
+  {
+    "//": "Keyword \`undefined\`",
+    data: [{ undefined: undefined }, undefined, [undefined]],
+  },
+
+  {
+    "//": "back-tick quoted strings",
+    data: [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      { "as-object-value": \`foo\` },
+    ],
+  },
+
+  { "//": "String escapes ", data: ["\\0", "\\xFF", "\\u00FF", \`\\u{1F409}\`] },
+
+  {
+    "//": "Numbers",
+    data: [0o123, 0b101010, 1e5, 123_456, 0xdeed_beef, 0123, -Infinity, -NaN],
+  },
+
+  { "//": "empty members", data: [[,], [1, , 2, , , ,], [1, , 2], [1, , 2]] },
+]
+
+================================================================================
+`;
+
+exports[`json6.json format 3`] = `
+====================================options=====================================
+parsers: ["json-stringify"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+[
+{'//': 'Keyword \`undefined\`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      \`\`,
+      \`foo\`,
+      \`
+  multiple-line
+\`,
+      \`\\u{1F409}\\\`'"\\\${}\`,
+      {'as-object-value': \`foo\`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\\0', '\\xFF', '\\u00FF', \`\\u{1F409}\`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]
+
+=====================================output=====================================
+[
+  {
+    "//": "Keyword \`undefined\`",
+    "data": [
+      {
+        "undefined": undefined
+      },
+      undefined,
+      [
+        undefined
+      ]
+    ]
+  },
+  {
+    "//": "back-tick quoted strings",
+    "data": [
+      "",
+      "foo",
+      "\\n  multiple-line\\n",
+      "🐉\`'\\"\${}",
+      {
+        "as-object-value": "foo"
+      }
+    ]
+  },
+  {
+    "//": "String escapes ",
+    "data": [
+      "\\u0000",
+      "ÿ",
+      "ÿ",
+      "🐉"
+    ]
+  },
+  {
+    "//": "Numbers",
+    "data": [
+      83,
+      42,
+      100000,
+      123456,
+      3740122863,
+      83,
+      -Infinity,
+      -NaN
+    ]
+  },
+  {
+    "//": "empty members",
+    "data": [
+      [
+        null
+      ],
+      [
+        1,
+        null,
+        2,
+        null,
+        null,
+        null
+      ],
+      [
+        1,
+        null,
+        2
+      ],
+      [
+        1,
+        null,
+        2
+      ]
+    ]
+  }
+]
+
+================================================================================
+`;
+
 exports[`key-value.json - {"trailingComma":"all"} format 1`] = `
 ====================================options=====================================
 parsers: ["json"]

tests/json/json/json6.json

@@ -0,0 +1,44 @@
+[
+{'//': 'Keyword `undefined`',
+    "data": [
+      {undefined: undefined},
+      undefined,
+      [undefined, ]
+    ]
+  },
+
+{'//': 'back-tick quoted strings',
+    "data": [
+      ``,
+      `foo`,
+      `
+  multiple-line
+`,
+      `\u{1F409}\`'"\${}`,
+      {'as-object-value': `foo`}
+    ]
+  },
+
+{'//': 'String escapes ',
+    "data": [
+      '\0', '\xFF', '\u00FF', `\u{1F409}`
+    ]
+  },
+
+{'//': 'Numbers',
+    "data": [
+      0o123, 0b101010, 1e5, 123_456, 0xDeeD_Beef,
+      0123,
+      -Infinity, -NaN,
+    ]
+  },
+
+{'//': 'empty members',
+    data: [
+      [,],
+      [1, , 2,,,,],
+      [1, , 2],
+      [1, , 2,]
+    ]
+  }
+]

tests/misc/errors/json/__snapshots__/jsfmt.spec.js.snap

@@ -73,439 +73,421 @@ exports[`snippet: #3 [json5] format 1`] = `
 `;
 
 exports[`snippet: #4 [json] format 1`] = `
-"Identifier 'undefined' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": undefined}
-    |         ^^^^^^^^^"
+"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
+> 1 | {\\"foo\\": () => {}}
+    |         ^^^^^^^^"
 `;
 
 exports[`snippet: #4 [json-stringify] format 1`] = `
-"Identifier 'undefined' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": undefined}
-    |         ^^^^^^^^^"
+"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
+> 1 | {\\"foo\\": () => {}}
+    |         ^^^^^^^^"
 `;
 
 exports[`snippet: #4 [json5] format 1`] = `
-"Identifier 'undefined' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": undefined}
-    |         ^^^^^^^^^"
+"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
+> 1 | {\\"foo\\": () => {}}
+    |         ^^^^^^^^"
 `;
 
 exports[`snippet: #5 [json] format 1`] = `
-"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": () => {}}
-    |         ^^^^^^^^"
+"Expecting Unicode escape sequence \\\\uXXXX (1:10)
+> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
+    |          ^"
 `;
 
 exports[`snippet: #5 [json-stringify] format 1`] = `
-"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": () => {}}
-    |         ^^^^^^^^"
+"Expecting Unicode escape sequence \\\\uXXXX (1:10)
+> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
+    |          ^"
 `;
 
 exports[`snippet: #5 [json5] format 1`] = `
-"'ArrowFunctionExpression' is not allowed in JSON. (1:9)
-> 1 | {\\"foo\\": () => {}}
-    |         ^^^^^^^^"
+"Expecting Unicode escape sequence \\\\uXXXX (1:10)
+> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
+    |          ^"
 `;
 
 exports[`snippet: #6 [json] format 1`] = `
-"Expecting Unicode escape sequence \\\\uXXXX (1:10)
-> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
-    |          ^"
+"'BinaryExpression' is not allowed in JSON. (1:1)
+> 1 | 1+2
+    | ^^^"
 `;
 
 exports[`snippet: #6 [json-stringify] format 1`] = `
-"Expecting Unicode escape sequence \\\\uXXXX (1:10)
-> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
-    |          ^"
+"'BinaryExpression' is not allowed in JSON. (1:1)
+> 1 | 1+2
+    | ^^^"
 `;
 
 exports[`snippet: #6 [json5] format 1`] = `
-"Expecting Unicode escape sequence \\\\uXXXX (1:10)
-> 1 | packages\\\\the-hub\\\\cypress\\\\fixtures\\\\gridConfiguration.json
-    |          ^"
+"'BinaryExpression' is not allowed in JSON. (1:1)
+> 1 | 1+2
+    | ^^^"
 `;
 
 exports[`snippet: #7 [json] format 1`] = `
-"'BinaryExpression' is not allowed in JSON. (1:1)
-> 1 | 1+2
-    | ^^^"
+"Shorthand property is not allowed in JSON. (1:2)
+> 1 | {Infinity}
+    |  ^^^^^^^^"
 `;
 
 exports[`snippet: #7 [json-stringify] format 1`] = `
-"'BinaryExpression' is not allowed in JSON. (1:1)
-> 1 | 1+2
-    | ^^^"
+"Shorthand property is not allowed in JSON. (1:2)
+> 1 | {Infinity}
+    |  ^^^^^^^^"
 `;
 
 exports[`snippet: #7 [json5] format 1`] = `
-"'BinaryExpression' is not allowed in JSON. (1:1)
-> 1 | 1+2
-    | ^^^"
+"Shorthand property is not allowed in JSON. (1:2)
+> 1 | {Infinity}
+    |  ^^^^^^^^"
 `;
 
 exports[`snippet: #8 [json] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [,]
-    | ^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key]: 1}
+    |   ^^^"
 `;
 
 exports[`snippet: #8 [json-stringify] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [,]
-    | ^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key]: 1}
+    |   ^^^"
 `;
 
 exports[`snippet: #8 [json5] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [,]
-    | ^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key]: 1}
+    |   ^^^"
 `;
 
 exports[`snippet: #9 [json] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [1,,2]
-    | ^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key()]: 1}
+    |   ^^^^^"
 `;
 
 exports[`snippet: #9 [json-stringify] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [1,,2]
-    | ^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key()]: 1}
+    |   ^^^^^"
 `;
 
 exports[`snippet: #9 [json5] format 1`] = `
-"Sparse array is not allowed in JSON. (1:1)
-> 1 | [1,,2]
-    | ^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {[key()]: 1}
+    |   ^^^^^"
 `;
 
 exports[`snippet: #10 [json] format 1`] = `
-"Shorthand property is not allowed in JSON. (1:2)
-> 1 | {Infinity}
-    |  ^^^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {['CallExpression']: 1}
+    |   ^^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #10 [json-stringify] format 1`] = `
-"Shorthand property is not allowed in JSON. (1:2)
-> 1 | {Infinity}
-    |  ^^^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {['CallExpression']: 1}
+    |   ^^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #10 [json5] format 1`] = `
-"Shorthand property is not allowed in JSON. (1:2)
-> 1 | {Infinity}
-    |  ^^^^^^^^"
+"Computed key is not allowed in JSON. (1:3)
+> 1 | {['CallExpression']: 1}
+    |   ^^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #11 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key]: 1}
-    |   ^^^"
+> 1 | {['StringLiteral']: 1}
+    |   ^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #11 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key]: 1}
-    |   ^^^"
+> 1 | {['StringLiteral']: 1}
+    |   ^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #11 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key]: 1}
-    |   ^^^"
+> 1 | {['StringLiteral']: 1}
+    |   ^^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #12 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key()]: 1}
-    |   ^^^^^"
+> 1 | {['string']: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #12 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key()]: 1}
-    |   ^^^^^"
+> 1 | {['string']: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #12 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[key()]: 1}
-    |   ^^^^^"
+> 1 | {['string']: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #13 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['CallExpression']: 1}
-    |   ^^^^^^^^^^^^^^^^"
+> 1 | {[1]: 1}
+    |   ^"
 `;
 
 exports[`snippet: #13 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['CallExpression']: 1}
-    |   ^^^^^^^^^^^^^^^^"
+> 1 | {[1]: 1}
+    |   ^"
 `;
 
 exports[`snippet: #13 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['CallExpression']: 1}
-    |   ^^^^^^^^^^^^^^^^"
+> 1 | {[1]: 1}
+    |   ^"
 `;
 
 exports[`snippet: #14 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['StringLiteral']: 1}
-    |   ^^^^^^^^^^^^^^^"
+> 1 | {[Infinity]: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #14 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['StringLiteral']: 1}
-    |   ^^^^^^^^^^^^^^^"
+> 1 | {[Infinity]: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #14 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['StringLiteral']: 1}
-    |   ^^^^^^^^^^^^^^^"
+> 1 | {[Infinity]: 1}
+    |   ^^^^^^^^"
 `;
 
 exports[`snippet: #15 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['string']: 1}
-    |   ^^^^^^^^"
+> 1 | {[-Infinity]: 1}
+    |   ^^^^^^^^^"
 `;
 
 exports[`snippet: #15 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['string']: 1}
-    |   ^^^^^^^^"
+> 1 | {[-Infinity]: 1}
+    |   ^^^^^^^^^"
 `;
 
 exports[`snippet: #15 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {['string']: 1}
-    |   ^^^^^^^^"
+> 1 | {[-Infinity]: 1}
+    |   ^^^^^^^^^"
 `;
 
 exports[`snippet: #16 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[1]: 1}
-    |   ^"
+> 1 | {[{key: 'value'}]: 1}
+    |   ^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #16 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[1]: 1}
-    |   ^"
+> 1 | {[{key: 'value'}]: 1}
+    |   ^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #16 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[1]: 1}
-    |   ^"
+> 1 | {[{key: 'value'}]: 1}
+    |   ^^^^^^^^^^^^^^"
 `;
 
 exports[`snippet: #17 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[Infinity]: 1}
-    |   ^^^^^^^^"
+> 1 | {[[]]: 1}
+    |   ^^"
 `;
 
 exports[`snippet: #17 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[Infinity]: 1}
-    |   ^^^^^^^^"
+> 1 | {[[]]: 1}
+    |   ^^"
 `;
 
 exports[`snippet: #17 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[Infinity]: 1}
-    |   ^^^^^^^^"
+> 1 | {[[]]: 1}
+    |   ^^"
 `;
 
 exports[`snippet: #18 [json] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[-Infinity]: 1}
-    |   ^^^^^^^^^"
+> 1 | {[null]: 1}
+    |   ^^^^"
 `;
 
 exports[`snippet: #18 [json-stringify] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[-Infinity]: 1}
-    |   ^^^^^^^^^"
+> 1 | {[null]: 1}
+    |   ^^^^"
 `;
 
 exports[`snippet: #18 [json5] format 1`] = `
 "Computed key is not allowed in JSON. (1:3)
-> 1 | {[-Infinity]: 1}
-    |   ^^^^^^^^^"
+> 1 | {[null]: 1}
+    |   ^^^^"
 `;
 
 exports[`snippet: #19 [json] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[{key: 'value'}]: 1}
-    |   ^^^^^^^^^^^^^^"
+"'CallExpression' is not allowed in JSON. (1:8)
+> 1 | {key: +foo()}
+    |        ^^^^^"
 `;
 
 exports[`snippet: #19 [json-stringify] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[{key: 'value'}]: 1}
-    |   ^^^^^^^^^^^^^^"
+"'CallExpression' is not allowed in JSON. (1:8)
+> 1 | {key: +foo()}
+    |        ^^^^^"
 `;
 
 exports[`snippet: #19 [json5] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[{key: 'value'}]: 1}
-    |   ^^^^^^^^^^^^^^"
+"'CallExpression' is not allowed in JSON. (1:8)
+> 1 | {key: +foo()}
+    |        ^^^^^"
 `;
 
 exports[`snippet: #20 [json] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[[]]: 1}
-    |   ^^"
+"Operator 'void' is not allowed in JSON. (1:7)
+> 1 | {key: void foo()}
+    |       ^^^^^^^^^^"
 `;
 
 exports[`snippet: #20 [json-stringify] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[[]]: 1}
-    |   ^^"
+"Operator 'void' is not allowed in JSON. (1:7)
+> 1 | {key: void foo()}
+    |       ^^^^^^^^^^"
 `;
 
 exports[`snippet: #20 [json5] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[[]]: 1}
-    |   ^^"
+"Operator 'void' is not allowed in JSON. (1:7)
+> 1 | {key: void foo()}
+    |       ^^^^^^^^^^"
 `;
 
 exports[`snippet: #21 [json] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[null]: 1}
-    |   ^^^^"
+"Unexpected token (1:1)
+> 1 | #!/usr/bin/env node
+    | ^
+  2 | {}"
 `;
 
 exports[`snippet: #21 [json-stringify] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[null]: 1}
-    |   ^^^^"
+"Unexpected token (1:1)
+> 1 | #!/usr/bin/env node
+    | ^
+  2 | {}"
 `;
 
 exports[`snippet: #21 [json5] format 1`] = `
-"Computed key is not allowed in JSON. (1:3)
-> 1 | {[null]: 1}
-    |   ^^^^"
+"Unexpected token (1:1)
+> 1 | #!/usr/bin/env node
+    | ^
+  2 | {}"
 `;
 
 exports[`snippet: #22 [json] format 1`] = `
-"'CallExpression' is not allowed in JSON. (1:8)
-> 1 | {key: +foo()}
-    |        ^^^^^"
+"Unexpected token (2:1)
+  1 | \\"use strict\\"
+> 2 | {}
+    | ^"
 `;
 
 exports[`snippet: #22 [json-stringify] format 1`] = `
-"'CallExpression' is not allowed in JSON. (1:8)
-> 1 | {key: +foo()}
-    |        ^^^^^"
+"Unexpected token (2:1)
+  1 | \\"use strict\\"
+> 2 | {}
+    | ^"
 `;
 
 exports[`snippet: #22 [json5] format 1`] = `
-"'CallExpression' is not allowed in JSON. (1:8)
-> 1 | {key: +foo()}
-    |        ^^^^^"
+"Unexpected token (2:1)
+  1 | \\"use strict\\"
+> 2 | {}
+    | ^"
 `;
 
 exports[`snippet: #23 [json] format 1`] = `
-"Operator 'void' is not allowed in JSON. (1:7)
-> 1 | {key: void foo()}
-    |       ^^^^^^^^^^"
+"Unexpected token (1:14)
+> 1 | /* comment */
+    |              ^"
 `;
 
 exports[`snippet: #23 [json-stringify] format 1`] = `
-"Operator 'void' is not allowed in JSON. (1:7)
-> 1 | {key: void foo()}
-    |       ^^^^^^^^^^"
+"Unexpected token (1:14)
+> 1 | /* comment */
+    |              ^"
 `;
 
 exports[`snippet: #23 [json5] format 1`] = `
-"Operator 'void' is not allowed in JSON. (1:7)
-> 1 | {key: void foo()}
-    |       ^^^^^^^^^^"
+"Unexpected token (1:14)
+> 1 | /* comment */
+    |              ^"
 `;
 
 exports[`snippet: #24 [json] format 1`] = `
-"Unexpected token (1:1)
-> 1 | #!/usr/bin/env node
-    | ^
-  2 | {}"
+"Unexpected token (1:11)
+> 1 | // comment
+    |           ^"
 `;
 
 exports[`snippet: #24 [json-stringify] format 1`] = `
-"Unexpected token (1:1)
-> 1 | #!/usr/bin/env node
-    | ^
-  2 | {}"
+"Unexpected token (1:11)
+> 1 | // comment
+    |           ^"
 `;
 
 exports[`snippet: #24 [json5] format 1`] = `
-"Unexpected token (1:1)
-> 1 | #!/usr/bin/env node
-    | ^
-  2 | {}"
+"Unexpected token (1:11)
+> 1 | // comment
+    |           ^"
 `;
 
 exports[`snippet: #25 [json] format 1`] = `
-"Unexpected token (2:1)
-  1 | \\"use strict\\"
-> 2 | {}
-    | ^"
+"'TemplateLiteral' with expression is not allowed in JSON. (1:7)
+> 1 | \`foo\${1}bar\`
+    |       ^"
 `;
 
 exports[`snippet: #25 [json-stringify] format 1`] = `
-"Unexpected token (2:1)
-  1 | \\"use strict\\"
-> 2 | {}
-    | ^"
+"'TemplateLiteral' with expression is not allowed in JSON. (1:7)
+> 1 | \`foo\${1}bar\`
+    |       ^"
 `;
 
 exports[`snippet: #25 [json5] format 1`] = `
-"Unexpected token (2:1)
-  1 | \\"use strict\\"
-> 2 | {}
-    | ^"
+"'TemplateLiteral' with expression is not allowed in JSON. (1:7)
+> 1 | \`foo\${1}bar\`
+    |       ^"
 `;
 
 exports[`snippet: #26 [json] format 1`] = `
-"Unexpected token (1:14)
-> 1 | /* comment */
-    |              ^"
+"Invalid left-hand side in prefix operation (1:5)
+> 1 | ----123
+    |     ^"
 `;
 
 exports[`snippet: #26 [json-stringify] format 1`] = `
-"Unexpected token (1:14)
-> 1 | /* comment */
-    |              ^"
+"Invalid left-hand side in prefix operation (1:5)
+> 1 | ----123
+    |     ^"
 `;
 
 exports[`snippet: #26 [json5] format 1`] = `
-"Unexpected token (1:14)
-> 1 | /* comment */
-    |              ^"
-`;
-
-exports[`snippet: #27 [json] format 1`] = `
-"Unexpected token (1:11)
-> 1 | // comment
-    |           ^"
-`;
-
-exports[`snippet: #27 [json-stringify] format 1`] = `
-"Unexpected token (1:11)
-> 1 | // comment
-    |           ^"
-`;
-
-exports[`snippet: #27 [json5] format 1`] = `
-"Unexpected token (1:11)
-> 1 | // comment
-    |           ^"
+"Invalid left-hand side in prefix operation (1:5)
+> 1 | ----123
+    |     ^"
 `;

tests/misc/errors/json/jsfmt.spec.js

@@ -6,12 +6,9 @@ run_spec(
       '{["foo"]:"bar"}',
       '{"foo": ~1}',
       '{"foo": false || "bar"}',
-      '{"foo": undefined}',
       '{"foo": () => {}}',
       "packages\\the-hub\\cypress\\fixtures\\gridConfiguration.json",
       "1+2",
-      "[,]",
-      "[1,,2]",
       "{Infinity}",
       "{[key]: 1}",
       "{[key()]: 1}",
@@ -30,6 +27,9 @@ run_spec(
       '"use strict"\n{}',
       "/* comment */",
       "// comment",
+      "`foo${1}bar`",
+      // JSON6 allow this, but babel can't parse
+      "----123",
     ],
   },
   ["json", "json5", "json-stringify"]