Commit 889c6efa authored by Mark Banner's avatar Mark Banner
Browse files

Bug 1768031 - Reject top-level await in modules via an ESLint rule. r=Gijs 

Differential Revision: https://phabricator.services.mozilla.com/D145892
parent 3dde0f67

docs/code-quality/lint/linters/eslint-plugin-mozilla.rst

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@@ -54,6 +54,7 @@ The plugin implements the following rules: 
   eslint-plugin-mozilla/reject-requires-await

   eslint-plugin-mozilla/reject-scriptableunicodeconverter

   eslint-plugin-mozilla/reject-some-requires

   eslint-plugin-mozilla/reject-top-level-await

   eslint-plugin-mozilla/use-cc-etc

   eslint-plugin-mozilla/use-chromeutils-generateqi

   eslint-plugin-mozilla/use-chromeutils-import

docs/code-quality/lint/linters/eslint-plugin-mozilla/reject-top-level-await.rst

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reject-top-level-await

======================



Rejects ``await`` at the top-level of code in modules. Top-level ``await`` is

not currently support in Gecko's component modules, so this is rejected.



Examples of incorrect code for this rule:

-----------------------------------------



.. code-block:: js



    await foo;



    if (expr) {

      await foo;

    }



    for await (let x of [1, 2, 3]) { }



Examples of correct code for this rule:

---------------------------------------



.. code-block:: js



    async function() { await foo; }

    async function() { for await (let x of [1, 2, 3]) { } }

tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js

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@@ -49,6 +49,7 @@ module.exports = { 
      },

      files: ["**/*.mjs", "**/*.jsm", "**/*.jsm.js"],

      rules: {

        "mozilla/reject-top-level-await": "error",

        // Bug 1703953: We don't have a good way to check a file runs in a

        // privilieged context. Apply this for jsm files as we know those are

        // privilieged, and then include more directories elsewhere.

tools/lint/eslint/eslint-plugin-mozilla/lib/index.js

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@@ -59,6 +59,7 @@ module.exports = { 
    "reject-scriptableunicodeconverter": require("../lib/rules/reject-scriptableunicodeconverter"),

    "reject-relative-requires": require("../lib/rules/reject-relative-requires"),

    "reject-some-requires": require("../lib/rules/reject-some-requires"),

    "reject-top-level-await": require("../lib/rules/reject-top-level-await"),

    "rejects-requires-await": require("../lib/rules/rejects-requires-await"),

    "use-cc-etc": require("../lib/rules/use-cc-etc"),

    "use-chromeutils-generateqi": require("../lib/rules/use-chromeutils-generateqi"),

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-top-level-await.js

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/**

 * @fileoverview Don't allow only() in tests

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 */



"use strict";



var helpers = require("../helpers");



module.exports = {

  meta: {

    docs: {

      url:

        "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/reject-top-level-await.html",

    },

    messages: {

      rejectTopLevelAwait:

        "Top-level await is not currently supported in component files.",

    },

    type: "problem",

  },



  create(context) {

    return {

      AwaitExpression(node) {

        if (!helpers.getIsGlobalScope(context.getAncestors())) {

          return;

        }

        context.report({ node, messageId: "rejectTopLevelAwait" });

      },

      ForOfStatement(node) {

        if (!node.await || !helpers.getIsGlobalScope(context.getAncestors())) {

          return;

        }

        context.report({ node, messageId: "rejectTopLevelAwait" });

      },

    };

  },

};