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diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-useless-parameters.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-useless-parameters.js
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+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-useless-parameters.js
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+/**
+ * @fileoverview Reject common XPCOM methods called with useless optional
+ * parameters, or non-existent parameters.
+ *
+ * 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";
+
+module.exports = {
+ meta: {
+ docs: {
+ url: "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/no-useless-parameters.html",
+ },
+ fixable: "code",
+ messages: {
+ newURIParams: "newURI's last parameters are optional.",
+ obmittedWhenFalse:
+ "{{fnName}}'s {{index}} parameter can be omitted when it's false.",
+ onlyTakes: "{{fnName}} only takes {{params}}",
+ },
+ schema: [],
+ type: "suggestion",
+ },
+
+ create(context) {
+ function getRangeAfterArgToEnd(argNumber, args) {
+ let sourceCode = context.getSourceCode();
+ return [
+ sourceCode.getTokenAfter(args[argNumber]).range[0],
+ args[args.length - 1].range[1],
+ ];
+ }
+
+ return {
+ CallExpression(node) {
+ let callee = node.callee;
+ if (
+ callee.type !== "MemberExpression" ||
+ callee.property.type !== "Identifier"
+ ) {
+ return;
+ }
+
+ let isFalse = arg => arg.type === "Literal" && arg.value === false;
+ let isFalsy = arg => arg.type === "Literal" && !arg.value;
+ let isBool = arg =>
+ arg.type === "Literal" && (arg.value === false || arg.value === true);
+ let name = callee.property.name;
+ let args = node.arguments;
+
+ if (
+ ["addEventListener", "removeEventListener", "addObserver"].includes(
+ name
+ ) &&
+ args.length === 3 &&
+ isFalse(args[2])
+ ) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(1, args));
+ },
+ messageId: "obmittedWhenFalse",
+ data: { fnName: name, index: "third" },
+ });
+ }
+
+ if (name === "clearUserPref" && args.length > 1) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(0, args));
+ },
+ messageId: "onlyTakes",
+ data: { fnName: name, params: "1 parameter" },
+ });
+ }
+
+ if (name === "removeObserver" && args.length === 3 && isBool(args[2])) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(1, args));
+ },
+ messageId: "onlyTakes",
+ data: { fnName: name, params: "2 parameters" },
+ });
+ }
+
+ if (name === "appendElement" && args.length === 2 && isFalse(args[1])) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(0, args));
+ },
+ messageId: "obmittedWhenFalse",
+ data: { fnName: name, index: "second" },
+ });
+ }
+
+ if (
+ name === "notifyObservers" &&
+ args.length === 3 &&
+ isFalsy(args[2])
+ ) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(1, args));
+ },
+ messageId: "obmittedWhenFalse",
+ data: { fnName: name, index: "third" },
+ });
+ }
+
+ if (
+ name === "getComputedStyle" &&
+ args.length === 2 &&
+ isFalsy(args[1])
+ ) {
+ context.report({
+ node,
+ fix: fixer => {
+ return fixer.removeRange(getRangeAfterArgToEnd(0, args));
+ },
+ messageId: "obmittedWhenFalse",
+ data: { fnName: "getComputedStyle", index: "second" },
+ });
+ }
+
+ if (
+ name === "newURI" &&
+ args.length > 1 &&
+ isFalsy(args[args.length - 1])
+ ) {
+ context.report({
+ node,
+ fix: fixer => {
+ if (args.length > 2 && isFalsy(args[args.length - 2])) {
+ return fixer.removeRange(getRangeAfterArgToEnd(0, args));
+ }
+
+ return fixer.removeRange(
+ getRangeAfterArgToEnd(args.length - 2, args)
+ );
+ },
+ messageId: "newURIParams",
+ });
+ }
+ },
+ };
+ },
+};