147 lines
5.5 KiB
JavaScript
147 lines
5.5 KiB
JavaScript
/**
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* @fileoverview Rule to check for implicit global variables, functions and classes.
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* @author Joshua Peek
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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type: "suggestion",
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docs: {
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description: "Disallow declarations in the global scope",
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recommended: false,
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url: "https://eslint.org/docs/latest/rules/no-implicit-globals"
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},
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schema: [{
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type: "object",
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properties: {
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lexicalBindings: {
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type: "boolean",
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default: false
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}
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},
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additionalProperties: false
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}],
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messages: {
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globalNonLexicalBinding: "Unexpected {{kind}} declaration in the global scope, wrap in an IIFE for a local variable, assign as global property for a global variable.",
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globalLexicalBinding: "Unexpected {{kind}} declaration in the global scope, wrap in a block or in an IIFE.",
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globalVariableLeak: "Global variable leak, declare the variable if it is intended to be local.",
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assignmentToReadonlyGlobal: "Unexpected assignment to read-only global variable.",
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redeclarationOfReadonlyGlobal: "Unexpected redeclaration of read-only global variable."
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}
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},
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create(context) {
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const checkLexicalBindings = context.options[0] && context.options[0].lexicalBindings === true;
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const sourceCode = context.sourceCode;
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/**
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* Reports the node.
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* @param {ASTNode} node Node to report.
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* @param {string} messageId Id of the message to report.
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* @param {string|undefined} kind Declaration kind, can be 'var', 'const', 'let', function or class.
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* @returns {void}
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*/
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function report(node, messageId, kind) {
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context.report({
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node,
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messageId,
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data: {
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kind
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}
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});
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}
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return {
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Program(node) {
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const scope = sourceCode.getScope(node);
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scope.variables.forEach(variable => {
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// Only ESLint global variables have the `writable` key.
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const isReadonlyEslintGlobalVariable = variable.writeable === false;
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const isWritableEslintGlobalVariable = variable.writeable === true;
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if (isWritableEslintGlobalVariable) {
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// Everything is allowed with writable ESLint global variables.
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return;
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}
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// Variables exported by "exported" block comments
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if (variable.eslintExported) {
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return;
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}
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variable.defs.forEach(def => {
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const defNode = def.node;
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if (def.type === "FunctionName" || (def.type === "Variable" && def.parent.kind === "var")) {
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if (isReadonlyEslintGlobalVariable) {
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report(defNode, "redeclarationOfReadonlyGlobal");
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} else {
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report(
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defNode,
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"globalNonLexicalBinding",
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def.type === "FunctionName" ? "function" : `'${def.parent.kind}'`
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);
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}
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}
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if (checkLexicalBindings) {
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if (def.type === "ClassName" ||
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(def.type === "Variable" && (def.parent.kind === "let" || def.parent.kind === "const"))) {
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if (isReadonlyEslintGlobalVariable) {
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report(defNode, "redeclarationOfReadonlyGlobal");
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} else {
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report(
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defNode,
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"globalLexicalBinding",
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def.type === "ClassName" ? "class" : `'${def.parent.kind}'`
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);
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}
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}
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}
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});
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});
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// Undeclared assigned variables.
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scope.implicit.variables.forEach(variable => {
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const scopeVariable = scope.set.get(variable.name);
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let messageId;
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if (scopeVariable) {
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// ESLint global variable
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if (scopeVariable.writeable) {
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return;
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}
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messageId = "assignmentToReadonlyGlobal";
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} else {
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// Reference to an unknown variable, possible global leak.
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messageId = "globalVariableLeak";
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}
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// def.node is an AssignmentExpression, ForInStatement or ForOfStatement.
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variable.defs.forEach(def => {
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report(def.node, messageId);
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});
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});
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}
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};
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}
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};
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