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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",
});
}
},
};
},
};
|
