1 | /**
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2 | * @fileoverview Rule to check multiple var declarations per line
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3 | * @author Alberto Rodríguez
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4 | */
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5 | ;
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6 |
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7 | //------------------------------------------------------------------------------
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8 | // Rule Definition
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9 | //------------------------------------------------------------------------------
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10 |
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11 | module.exports = {
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12 | meta: {
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13 | type: "suggestion",
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14 |
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15 | docs: {
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16 | description: "require or disallow newlines around variable declarations",
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17 | category: "Stylistic Issues",
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18 | recommended: false,
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19 | url: "https://eslint.org/docs/rules/one-var-declaration-per-line"
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20 | },
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21 |
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22 | schema: [
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23 | {
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24 | enum: ["always", "initializations"]
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25 | }
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26 | ],
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27 |
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28 | fixable: "whitespace",
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29 |
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30 | messages: {
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31 | expectVarOnNewline: "Expected variable declaration to be on a new line."
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32 | }
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33 | },
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34 |
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35 | create(context) {
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36 |
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37 | const always = context.options[0] === "always";
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38 |
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39 | //--------------------------------------------------------------------------
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40 | // Helpers
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41 | //--------------------------------------------------------------------------
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42 |
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43 |
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44 | /**
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45 | * Determine if provided keyword is a variant of for specifiers
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46 | * @private
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47 | * @param {string} keyword keyword to test
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48 | * @returns {boolean} True if `keyword` is a variant of for specifier
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49 | */
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50 | function isForTypeSpecifier(keyword) {
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51 | return keyword === "ForStatement" || keyword === "ForInStatement" || keyword === "ForOfStatement";
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52 | }
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53 |
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54 | /**
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55 | * Checks newlines around variable declarations.
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56 | * @private
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57 | * @param {ASTNode} node `VariableDeclaration` node to test
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58 | * @returns {void}
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59 | */
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60 | function checkForNewLine(node) {
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61 | if (isForTypeSpecifier(node.parent.type)) {
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62 | return;
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63 | }
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64 |
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65 | const declarations = node.declarations;
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66 | let prev;
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67 |
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68 | declarations.forEach(current => {
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69 | if (prev && prev.loc.end.line === current.loc.start.line) {
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70 | if (always || prev.init || current.init) {
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71 | context.report({
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72 | node,
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73 | messageId: "expectVarOnNewline",
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74 | loc: current.loc,
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75 | fix: fixer => fixer.insertTextBefore(current, "\n")
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76 | });
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77 | }
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78 | }
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79 | prev = current;
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80 | });
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81 | }
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82 |
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83 | //--------------------------------------------------------------------------
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84 | // Public
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85 | //--------------------------------------------------------------------------
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86 |
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87 | return {
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88 | VariableDeclaration: checkForNewLine
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89 | };
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90 |
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91 | }
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92 | };
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