1 | /**
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2 | * @fileoverview A rule to warn against using arrow functions when they could be
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3 | * confused with comparisions
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4 | * @author Jxck <https://github.com/Jxck>
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5 | */
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6 |
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7 | ;
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8 |
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9 | const astUtils = require("../ast-utils.js");
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10 |
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11 | //------------------------------------------------------------------------------
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12 | // Helpers
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13 | //------------------------------------------------------------------------------
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14 |
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15 | /**
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16 | * Checks whether or not a node is a conditional expression.
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17 | * @param {ASTNode} node - node to test
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18 | * @returns {boolean} `true` if the node is a conditional expression.
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19 | */
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20 | function isConditional(node) {
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21 | return node && node.type === "ConditionalExpression";
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22 | }
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23 |
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24 | //------------------------------------------------------------------------------
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25 | // Rule Definition
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26 | //------------------------------------------------------------------------------
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27 |
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28 | module.exports = {
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29 | meta: {
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30 | docs: {
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31 | description: "disallow arrow functions where they could be confused with comparisons",
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32 | category: "ECMAScript 6",
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33 | recommended: false
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34 | },
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35 |
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36 | schema: [{
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37 | type: "object",
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38 | properties: {
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39 | allowParens: {type: "boolean"}
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40 | },
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41 | additionalProperties: false
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42 | }]
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43 | },
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44 |
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45 | create(context) {
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46 | const config = context.options[0] || {};
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47 | const sourceCode = context.getSourceCode();
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48 |
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49 | /**
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50 | * Reports if an arrow function contains an ambiguous conditional.
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51 | * @param {ASTNode} node - A node to check and report.
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52 | * @returns {void}
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53 | */
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54 | function checkArrowFunc(node) {
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55 | const body = node.body;
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56 |
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57 | if (isConditional(body) && !(config.allowParens && astUtils.isParenthesised(sourceCode, body))) {
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58 | context.report(node, "Arrow function used ambiguously with a conditional expression.");
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59 | }
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60 | }
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61 |
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62 | return {
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63 | ArrowFunctionExpression: checkArrowFunc
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64 | };
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65 | }
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66 | };
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