| /** |
| * @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 |
| }); |
| }); |
| } |
| }; |
| } |
| }; |