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| /** | |
| * @fileoverview Rule to flag references to undeclared variables. | |
| * @author Mark Macdonald | |
| */ | |
| "use strict"; | |
| //------------------------------------------------------------------------------ | |
| // Helpers | |
| //------------------------------------------------------------------------------ | |
| /** | |
| * Checks if the given node is the argument of a typeof operator. | |
| * @param {ASTNode} node The AST node being checked. | |
| * @returns {boolean} Whether or not the node is the argument of a typeof operator. | |
| */ | |
| function hasTypeOfOperator(node) { | |
| const parent = node.parent; | |
| return parent.type === "UnaryExpression" && parent.operator === "typeof"; | |
| } | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
| module.exports = { | |
| meta: { | |
| type: "problem", | |
| docs: { | |
| description: "disallow the use of undeclared variables unless mentioned in `/*global */` comments", | |
| category: "Variables", | |
| recommended: true, | |
| url: "https://eslint.org/docs/rules/no-undef" | |
| }, | |
| schema: [ | |
| { | |
| type: "object", | |
| properties: { | |
| typeof: { | |
| type: "boolean", | |
| default: false | |
| } | |
| }, | |
| additionalProperties: false | |
| } | |
| ], | |
| messages: { | |
| undef: "'{{name}}' is not defined." | |
| } | |
| }, | |
| create(context) { | |
| const options = context.options[0]; | |
| const considerTypeOf = options && options.typeof === true || false; | |
| return { | |
| "Program:exit"(/* node */) { | |
| const globalScope = context.getScope(); | |
| globalScope.through.forEach(ref => { | |
| const identifier = ref.identifier; | |
| if (!considerTypeOf && hasTypeOfOperator(identifier)) { | |
| return; | |
| } | |
| context.report({ | |
| node: identifier, | |
| messageId: "undef", | |
| data: identifier | |
| }); | |
| }); | |
| } | |
| }; | |
| } | |
| }; |