1 | /**
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2 | * @fileoverview require default case in switch statements
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3 | * @author Aliaksei Shytkin
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4 | */
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5 | ;
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6 |
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7 | const DEFAULT_COMMENT_PATTERN = /^no default$/;
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8 |
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9 | //------------------------------------------------------------------------------
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10 | // Rule Definition
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11 | //------------------------------------------------------------------------------
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12 |
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13 | module.exports = {
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14 | meta: {
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15 | docs: {
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16 | description: "require `default` cases in `switch` statements",
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17 | category: "Best Practices",
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18 | recommended: false
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19 | },
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20 |
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21 | schema: [{
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22 | type: "object",
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23 | properties: {
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24 | commentPattern: {
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25 | type: "string"
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26 | }
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27 | },
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28 | additionalProperties: false
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29 | }]
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30 | },
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31 |
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32 | create(context) {
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33 | const options = context.options[0] || {};
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34 | const commentPattern = options.commentPattern ?
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35 | new RegExp(options.commentPattern) :
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36 | DEFAULT_COMMENT_PATTERN;
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37 |
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38 | const sourceCode = context.getSourceCode();
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39 |
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40 | //--------------------------------------------------------------------------
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41 | // Helpers
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42 | //--------------------------------------------------------------------------
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43 |
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44 | /**
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45 | * Shortcut to get last element of array
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46 | * @param {*[]} collection Array
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47 | * @returns {*} Last element
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48 | */
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49 | function last(collection) {
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50 | return collection[collection.length - 1];
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51 | }
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52 |
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53 | //--------------------------------------------------------------------------
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54 | // Public
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55 | //--------------------------------------------------------------------------
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56 |
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57 | return {
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58 |
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59 | SwitchStatement(node) {
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60 |
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61 | if (!node.cases.length) {
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62 |
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63 | /*
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64 | * skip check of empty switch because there is no easy way
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65 | * to extract comments inside it now
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66 | */
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67 | return;
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68 | }
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69 |
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70 | const hasDefault = node.cases.some(function(v) {
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71 | return v.test === null;
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72 | });
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73 |
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74 | if (!hasDefault) {
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75 |
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76 | let comment;
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77 |
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78 | const lastCase = last(node.cases);
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79 | const comments = sourceCode.getComments(lastCase).trailing;
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80 |
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81 | if (comments.length) {
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82 | comment = last(comments);
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83 | }
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84 |
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85 | if (!comment || !commentPattern.test(comment.value.trim())) {
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86 | context.report(node, "Expected a default case.");
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87 | }
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88 | }
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89 | }
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90 | };
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91 | }
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92 | };
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