86 lines
2.1 KiB
JavaScript
86 lines
2.1 KiB
JavaScript
/**
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* @fileoverview Rule to flag for-in loops without if statements inside
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* @author Nicholas C. Zakas
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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('../types').Rule.RuleModule} */
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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: 'Require `for-in` loops to include an `if` statement',
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recommended: false,
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url: 'https://eslint.org/docs/latest/rules/guard-for-in',
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},
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schema: [],
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messages: {
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wrap: 'The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype.',
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},
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},
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create(context) {
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return {
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ForInStatement(node) {
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const body = node.body;
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// empty statement
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if (body.type === 'EmptyStatement') {
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return;
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}
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// if statement
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if (body.type === 'IfStatement') {
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return;
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}
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// empty block
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if (body.type === 'BlockStatement' && body.body.length === 0) {
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return;
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}
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// block with just if statement
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if (
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body.type === 'BlockStatement' &&
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body.body.length === 1 &&
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body.body[0].type === 'IfStatement'
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) {
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return;
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}
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// block that starts with if statement
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if (
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body.type === 'BlockStatement' &&
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body.body.length >= 1 &&
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body.body[0].type === 'IfStatement'
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) {
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const i = body.body[0];
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// ... whose consequent is a continue
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if (i.consequent.type === 'ContinueStatement') {
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return;
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}
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// ... whose consequent is a block that contains only a continue
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if (
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i.consequent.type === 'BlockStatement' &&
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i.consequent.body.length === 1 &&
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i.consequent.body[0].type === 'ContinueStatement'
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) {
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return;
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}
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}
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context.report({ node, messageId: 'wrap' });
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},
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};
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},
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};
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