Current File : /var/www/html/node_modules/eslint/lib/rules/no-invalid-this.js
/**
* @fileoverview A rule to disallow `this` keywords outside of classes or class-like objects.
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Determines if the given code path is a code path with lexical `this` binding.
* That is, if `this` within the code path refers to `this` of surrounding code path.
* @param {CodePath} codePath Code path.
* @param {ASTNode} node Node that started the code path.
* @returns {boolean} `true` if it is a code path with lexical `this` binding.
*/
function isCodePathWithLexicalThis(codePath, node) {
return codePath.origin === "function" && node.type === "ArrowFunctionExpression";
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "disallow `this` keywords outside of classes or class-like objects",
recommended: false,
url: "https://eslint.org/docs/rules/no-invalid-this"
},
schema: [
{
type: "object",
properties: {
capIsConstructor: {
type: "boolean",
default: true
}
},
additionalProperties: false
}
],
messages: {
unexpectedThis: "Unexpected 'this'."
}
},
create(context) {
const options = context.options[0] || {};
const capIsConstructor = options.capIsConstructor !== false;
const stack = [],
sourceCode = context.getSourceCode();
/**
* Gets the current checking context.
*
* The return value has a flag that whether or not `this` keyword is valid.
* The flag is initialized when got at the first time.
* @returns {{valid: boolean}}
* an object which has a flag that whether or not `this` keyword is valid.
*/
stack.getCurrent = function() {
const current = this[this.length - 1];
if (!current.init) {
current.init = true;
current.valid = !astUtils.isDefaultThisBinding(
current.node,
sourceCode,
{ capIsConstructor }
);
}
return current;
};
return {
onCodePathStart(codePath, node) {
if (isCodePathWithLexicalThis(codePath, node)) {
return;
}
if (codePath.origin === "program") {
const scope = context.getScope();
const features = context.parserOptions.ecmaFeatures || {};
stack.push({
init: true,
node,
valid: !(
scope.isStrict ||
node.sourceType === "module" ||
(features.globalReturn && scope.childScopes[0].isStrict)
)
});
return;
}
/*
* `init: false` means that `valid` isn't determined yet.
* Most functions don't use `this`, and the calculation for `valid`
* is relatively costly, so we'll calculate it lazily when the first
* `this` within the function is traversed. A special case are non-strict
* functions, because `this` refers to the global object and therefore is
* always valid, so we can set `init: true` right away.
*/
stack.push({
init: !context.getScope().isStrict,
node,
valid: true
});
},
onCodePathEnd(codePath, node) {
if (isCodePathWithLexicalThis(codePath, node)) {
return;
}
stack.pop();
},
// Reports if `this` of the current context is invalid.
ThisExpression(node) {
const current = stack.getCurrent();
if (current && !current.valid) {
context.report({
node,
messageId: "unexpectedThis"
});
}
}
};
}
};
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