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/**
* @fileoverview Warn when idempotent methods are called and their return value is unused.
*
* 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: {
useReturnValue:
"{Array/String}.{{ property }} doesn't modify the instance in-place",
},
schema: [],
type: "problem",
},
create(context) {
return {
ExpressionStatement(node) {
if (
node.expression?.type != "CallExpression" ||
node.expression.callee?.type != "MemberExpression" ||
node.expression.callee.property?.type != "Identifier" ||
!["concat", "join", "slice"].includes(
node.expression.callee.property?.name
)
) {
return;
}
context.report({
node,
messageId: "useReturnValue",
data: {
property: node.expression.callee.property.name,
},
});
},
};
},
};