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/**
* @fileoverview Prefers Object.hasOwn() instead of Object.prototype.hasOwnProperty.call()
* @author Nitin Kumar
* @author Gautam Arora
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Checks if the given node is considered to be an access to a property of `Object.prototype`.
* @param {ASTNode} node `MemberExpression` node to evaluate.
* @returns {boolean} `true` if `node.object` is `Object`, `Object.prototype`, or `{}` (empty 'ObjectExpression' node).
*/
function hasLeftHandObject(node) {
/*
* ({}).hasOwnProperty.call(obj, prop) - `true`
* ({ foo }.hasOwnProperty.call(obj, prop)) - `false`, object literal should be empty
*/
if (node.object.type === "ObjectExpression" && node.object.properties.length === 0) {
return true;
}
const objectNodeToCheck = node.object.type === "MemberExpression" && astUtils.getStaticPropertyName(node.object) === "prototype" ? node.object.object : node.object;
if (objectNodeToCheck.type === "Identifier" && objectNodeToCheck.name === "Object") {
return true;
}
return false;
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description:
"Disallow use of `Object.prototype.hasOwnProperty.call()` and prefer use of `Object.hasOwn()`",
recommended: false,
url: "https://eslint.org/docs/latest/rules/prefer-object-has-own"
},
schema: [],
messages: {
useHasOwn: "Use 'Object.hasOwn()' instead of 'Object.prototype.hasOwnProperty.call()'."
},
fixable: "code"
},
create(context) {
const sourceCode = context.sourceCode;
return {
CallExpression(node) {
if (!(node.callee.type === "MemberExpression" && node.callee.object.type === "MemberExpression")) {
return;
}
const calleePropertyName = astUtils.getStaticPropertyName(node.callee);
const objectPropertyName = astUtils.getStaticPropertyName(node.callee.object);
const isObject = hasLeftHandObject(node.callee.object);
// check `Object` scope
const scope = sourceCode.getScope(node);
const variable = astUtils.getVariableByName(scope, "Object");
if (
calleePropertyName === "call" &&
objectPropertyName === "hasOwnProperty" &&
isObject &&
variable && variable.scope.type === "global"
) {
context.report({
node,
messageId: "useHasOwn",
fix(fixer) {
if (sourceCode.getCommentsInside(node.callee).length > 0) {
return null;
}
const tokenJustBeforeNode = sourceCode.getTokenBefore(node.callee, { includeComments: true });
// for https://github.com/eslint/eslint/pull/15346#issuecomment-991417335
if (
tokenJustBeforeNode &&
tokenJustBeforeNode.range[1] === node.callee.range[0] &&
!astUtils.canTokensBeAdjacent(tokenJustBeforeNode, "Object.hasOwn")
) {
return fixer.replaceText(node.callee, " Object.hasOwn");
}
return fixer.replaceText(node.callee, "Object.hasOwn");
}
});
}
}
};
}
};