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/**
* @fileoverview Reject calls to removeEventListenter where {once: true} could
* be used instead.
*
* 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
*/
"use strict";
module.exports = {
meta: {
docs: {
},
messages: {
useOnce:
"use {once: true} instead of removeEventListener as the first instruction of the listener",
},
schema: [],
type: "suggestion",
},
create(context) {
return {
CallExpression(node) {
let callee = node.callee;
if (
callee.type !== "MemberExpression" ||
callee.property.type !== "Identifier" ||
callee.property.name !== "addEventListener" ||
node.arguments.length == 4
) {
return;
}
let listener = node.arguments[1];
if (
!listener ||
listener.type != "FunctionExpression" ||
!listener.body ||
listener.body.type != "BlockStatement" ||
!listener.body.body.length ||
listener.body.body[0].type != "ExpressionStatement" ||
listener.body.body[0].expression.type != "CallExpression"
) {
return;
}
let call = listener.body.body[0].expression;
if (
call.callee.type == "MemberExpression" &&
call.callee.property.type == "Identifier" &&
call.callee.property.name == "removeEventListener" &&
((call.arguments[0].type == "Literal" &&
call.arguments[0].value == node.arguments[0].value) ||
(call.arguments[0].type == "Identifier" &&
call.arguments[0].name == node.arguments[0].name))
) {
context.report({
node: call,
messageId: "useOnce",
});
}
},
};
},
};