88 lines
2.8 KiB
JavaScript
88 lines
2.8 KiB
JavaScript
/**
|
|
* @fileoverview A rule to suggest using of the spread operator instead of `.apply()`.
|
|
* @author Toru Nagashima
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
const astUtils = require("./utils/ast-utils");
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Helpers
|
|
//------------------------------------------------------------------------------
|
|
|
|
/**
|
|
* Checks whether or not a node is a `.apply()` for variadic.
|
|
* @param {ASTNode} node A CallExpression node to check.
|
|
* @returns {boolean} Whether or not the node is a `.apply()` for variadic.
|
|
*/
|
|
function isVariadicApplyCalling(node) {
|
|
return (
|
|
astUtils.isSpecificMemberAccess(node.callee, null, "apply") &&
|
|
node.arguments.length === 2 &&
|
|
node.arguments[1].type !== "ArrayExpression" &&
|
|
node.arguments[1].type !== "SpreadElement"
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Checks whether or not `thisArg` is not changed by `.apply()`.
|
|
* @param {ASTNode|null} expectedThis The node that is the owner of the applied function.
|
|
* @param {ASTNode} thisArg The node that is given to the first argument of the `.apply()`.
|
|
* @param {RuleContext} context The ESLint rule context object.
|
|
* @returns {boolean} Whether or not `thisArg` is not changed by `.apply()`.
|
|
*/
|
|
function isValidThisArg(expectedThis, thisArg, context) {
|
|
if (!expectedThis) {
|
|
return astUtils.isNullOrUndefined(thisArg);
|
|
}
|
|
return astUtils.equalTokens(expectedThis, thisArg, context);
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
module.exports = {
|
|
meta: {
|
|
type: "suggestion",
|
|
|
|
docs: {
|
|
description: "require spread operators instead of `.apply()`",
|
|
category: "ECMAScript 6",
|
|
recommended: false,
|
|
url: "https://eslint.org/docs/rules/prefer-spread"
|
|
},
|
|
|
|
schema: [],
|
|
fixable: null,
|
|
|
|
messages: {
|
|
preferSpread: "Use the spread operator instead of '.apply()'."
|
|
}
|
|
},
|
|
|
|
create(context) {
|
|
const sourceCode = context.getSourceCode();
|
|
|
|
return {
|
|
CallExpression(node) {
|
|
if (!isVariadicApplyCalling(node)) {
|
|
return;
|
|
}
|
|
|
|
const applied = astUtils.skipChainExpression(astUtils.skipChainExpression(node.callee).object);
|
|
const expectedThis = (applied.type === "MemberExpression") ? applied.object : null;
|
|
const thisArg = node.arguments[0];
|
|
|
|
if (isValidThisArg(expectedThis, thisArg, sourceCode)) {
|
|
context.report({
|
|
node,
|
|
messageId: "preferSpread"
|
|
});
|
|
}
|
|
}
|
|
};
|
|
}
|
|
};
|