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/* 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,
"use strict";
/**
* The configuration is based on eslint:recommended config. The details for all
* the ESLint rules, and which ones are in the recommended configuration can
* be found here:
*
*
* Rules that we've explicitly decided not to enable:
*
* - This generates too many false positives that are not easy to work
* around, and false positives seem to be inherent in the rule.
* - Would be interested if this could apply to just vars, but at the moment
* it doesn't.
* max-depth
* - Don't enforce the maximum depth that blocks can be nested. The
* complexity rule is a better rule to check this.
* - This doesn't reveal any actual errors, and is a lot of work to address.
*/
module.exports = {
env: {
browser: true,
es2022: true,
"mozilla/privileged": true,
"mozilla/specific": true,
},
// The prettier configuration here comes from eslint-config-prettier and
// turns off all of ESLint's rules related to formatting.
extends: [
"eslint:recommended",
"prettier",
"plugin:json/recommended-with-comments",
],
overrides: [
{
// System mjs files and jsm files are not loaded in the browser scope,
// so we turn that off for those. Though we do have our own special
// environment for them.
env: {
browser: false,
"mozilla/sysmjs": true,
},
files: ["**/*.sys.mjs", "**/*.jsm"],
rules: {
"mozilla/lazy-getter-object-name": "error",
"mozilla/reject-eager-module-in-lazy-getter": "error",
"mozilla/reject-global-this": "error",
"mozilla/reject-globalThis-modification": "error",
// For all system modules, we expect no properties to need importing,
// hence reject everything.
"mozilla/reject-importGlobalProperties": ["error", "everything"],
"mozilla/reject-mixing-eager-and-lazy": "error",
"mozilla/reject-top-level-await": "error",
// We can enable builtinGlobals for jsms due to their scopes.
"no-redeclare": ["error", { builtinGlobals: false }],
},
},
{
files: ["**/*.mjs", "**/*.jsx", "**/*.jsm", "**/?(*.)worker.?(m)js"],
rules: {
// Modules and workers are far easier to check for no-unused-vars on a
// global scope, than our content files. Hence we turn that on here.
"no-unused-vars": [
"error",
{
argsIgnorePattern: "^_",
vars: "all",
},
],
},
},
{
excludedFiles: ["**/*.sys.mjs"],
files: ["**/*.mjs"],
rules: {
"mozilla/reject-import-system-module-from-non-system": "error",
"mozilla/reject-lazy-imports-into-globals": "error",
"no-shadow": ["error", { allow: ["event"], builtinGlobals: true }],
},
},
{
files: ["**/*.mjs", "**/*.jsx"],
parserOptions: {
sourceType: "module",
},
rules: {
"mozilla/use-static-import": "error",
// This rule defaults to not allowing "use strict" in module files since
// they are always loaded in strict mode.
strict: "error",
},
},
{
files: ["**/*.jsm"],
rules: {
"mozilla/mark-exported-symbols-as-used": "error",
},
},
{
env: {
browser: false,
"mozilla/privileged": false,
"mozilla/sjs": true,
"mozilla/specific": false,
},
files: ["**/*.sjs"],
rules: {
// For sjs files, reject everything as we should update the sandbox
// to include the globals we need, as these are test-only files.
"mozilla/reject-importGlobalProperties": ["error", "everything"],
},
},
{
env: {
browser: false,
worker: true,
},
files: [
// Most files should use the `.worker.` format to be consistent with
// other items like `.sys.mjs`, but we allow simply calling the file
// "worker" as well.
"**/?(*.)worker.?(m)js",
],
},
],
parserOptions: {
ecmaVersion: "latest",
},
// When adding items to this file please check for effects on sub-directories.
plugins: ["html", "json", "no-unsanitized"],
// When adding items to this file please check for effects on all of toolkit
// and browser
rules: {
// This may conflict with prettier, so we turn it off.
"arrow-body-style": "off",
// Warn about cyclomatic complexity in functions.
// XXX Get this down to 20?
complexity: ["error", 34],
// Functions must always return something or nothing
"consistent-return": "error",
// Require braces around blocks that start a new line
curly: ["error", "all"],
// Encourage the use of dot notation whenever possible.
"dot-notation": "error",
// Maximum depth callbacks can be nested.
"max-nested-callbacks": ["error", 10],
"mozilla/avoid-removeChild": "error",
"mozilla/consistent-if-bracing": "error",
"mozilla/import-browser-window-globals": "error",
"mozilla/import-globals": "error",
"mozilla/no-compare-against-boolean-literals": "error",
"mozilla/no-cu-reportError": "error",
"mozilla/no-define-cc-etc": "error",
"mozilla/no-throw-cr-literal": "error",
"mozilla/no-useless-parameters": "error",
"mozilla/no-useless-removeEventListener": "error",
"mozilla/prefer-boolean-length-check": "error",
"mozilla/prefer-formatValues": "error",
"mozilla/reject-addtask-only": "error",
"mozilla/reject-chromeutils-import": "error",
"mozilla/reject-chromeutils-import-params": "error",
"mozilla/reject-importGlobalProperties": ["error", "allownonwebidl"],
"mozilla/reject-multiple-getters-calls": "error",
"mozilla/reject-scriptableunicodeconverter": "warn",
"mozilla/rejects-requires-await": "error",
"mozilla/use-cc-etc": "error",
"mozilla/use-chromeutils-definelazygetter": "error",
"mozilla/use-chromeutils-generateqi": "error",
"mozilla/use-chromeutils-import": "error",
"mozilla/use-console-createInstance": "error",
"mozilla/use-default-preference-values": "error",
"mozilla/use-includes-instead-of-indexOf": "error",
"mozilla/use-isInstance": "error",
"mozilla/use-ownerGlobal": "error",
"mozilla/use-returnValue": "error",
"mozilla/use-services": "error",
"mozilla/valid-lazy": "error",
"mozilla/valid-services": "error",
// Use [] instead of Array()
"no-array-constructor": "error",
// Disallow use of arguments.caller or arguments.callee.
"no-caller": "error",
// Disallow the use of console, except for errors and warnings.
"no-console": ["error", { allow: ["createInstance", "error", "warn"] }],
// Disallows expressions where the operation doesn't affect the value.
// TODO: This is enabled by default in ESLint's v9 recommended configuration.
"no-constant-binary-expression": "error",
// If an if block ends with a return no need for an else block
"no-else-return": "error",
// No empty statements
"no-empty": ["error", { allowEmptyCatch: true }],
// Disallow empty static blocks.
// This rule will be a recommended rule in ESLint v9 so may be removed
// when we upgrade to that.
"no-empty-static-block": "error",
// Disallow eval and setInteral/setTimeout with strings
"no-eval": "error",
// Disallow unnecessary calls to .bind()
"no-extra-bind": "error",
// Disallow fallthrough of case statements
"no-fallthrough": [
"error",
{
// The eslint rule doesn't allow for case-insensitive regex option.
// The following pattern allows for a dash between "fall through" as
// well as alternate spelling of "fall thru". The pattern also allows
// for an optional "s" at the end of "fall" ("falls through").
commentPattern:
"[Ff][Aa][Ll][Ll][Ss]?[\\s-]?([Tt][Hh][Rr][Oo][Uu][Gg][Hh]|[Tt][Hh][Rr][Uu])",
},
],
// Disallow eval and setInteral/setTimeout with strings
"no-implied-eval": "error",
// See explicit decisions at top of file.
"no-inner-declarations": "off",
// Disallow the use of the __iterator__ property
"no-iterator": "error",
// No labels
"no-labels": "error",
// Disallow unnecessary nested blocks
"no-lone-blocks": "error",
// No single if block inside an else block
"no-lonely-if": "error",
// Nested ternary statements are confusing
"no-nested-ternary": "error",
// Disallow new operators with global non-constructor functions.
// This rule will be a recommended rule in ESLint v9 so may be removed
// when we upgrade to that.
"no-new-native-nonconstructor": "error",
// Disallow use of new wrappers
"no-new-wrappers": "error",
// Use {} instead of new Object(), unless arguments are passed.
"no-object-constructor": "error",
"no-prototype-builtins": "off",
// Disable builtinGlobals for no-redeclare as this conflicts with our
// globals declarations especially for browser window.
"no-redeclare": ["error", { builtinGlobals: false }],
// Disallow use of event global.
"no-restricted-globals": ["error", "event"],
// No unnecessary comparisons
"no-self-compare": "error",
// No comma sequenced statements
"no-sequences": "error",
// No declaring variables from an outer scope
// "no-shadow": "error",
// Disallow throwing literals (eg. throw "error" instead of
// throw new Error("error")).
"no-throw-literal": "error",
// Disallow the use of Boolean literals in conditional expressions.
"no-unneeded-ternary": "error",
// No unsanitized use of innerHTML=, document.write() etc.
"no-unsanitized/method": "error",
"no-unsanitized/property": "error",
// Disallow unused private class members.
// This rule will be a recommended rule in ESLint v9 so may be removed
// when we upgrade to that.
"no-unused-private-class-members": "error",
// No declaring variables that are never used
"no-unused-vars": [
"error",
{
argsIgnorePattern: "^_",
vars: "local",
},
],
// No using variables before defined
// "no-use-before-define": ["error", "nofunc"],
// Disallow unnecessary .call() and .apply()
"no-useless-call": "error",
// Don't concatenate string literals together (unless they span multiple
// lines)
"no-useless-concat": "error",
// See explicit decisions at top of file.
"no-useless-escape": "off",
// Disallow redundant return statements
"no-useless-return": "error",
// Require object-literal shorthand with ES6 method syntax
"object-shorthand": ["error", "always", { avoidQuotes: true }],
// This may conflict with prettier, so turn it off.
"prefer-arrow-callback": "off",
},
};