1 | /**
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2 | * @fileoverview Rule to enforce line breaks after each array element
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3 | * @author Jan Peer Stöcklmair <https://github.com/JPeer264>
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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 | const astUtils = require("./utils/ast-utils");
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9 |
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10 | //------------------------------------------------------------------------------
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11 | // Rule Definition
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12 | //------------------------------------------------------------------------------
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13 |
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14 | module.exports = {
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15 | meta: {
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16 | type: "layout",
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17 |
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18 | docs: {
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19 | description: "enforce line breaks after each array element",
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20 | category: "Stylistic Issues",
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21 | recommended: false,
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22 | url: "https://eslint.org/docs/rules/array-element-newline"
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23 | },
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24 |
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25 | fixable: "whitespace",
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26 |
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27 | schema: [
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28 | {
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29 | oneOf: [
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30 | {
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31 | enum: ["always", "never", "consistent"]
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32 | },
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33 | {
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34 | type: "object",
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35 | properties: {
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36 | multiline: {
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37 | type: "boolean"
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38 | },
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39 | minItems: {
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40 | type: ["integer", "null"],
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41 | minimum: 0
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42 | }
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43 | },
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44 | additionalProperties: false
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45 | }
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46 | ]
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47 | }
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48 | ],
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49 |
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50 | messages: {
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51 | unexpectedLineBreak: "There should be no linebreak here.",
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52 | missingLineBreak: "There should be a linebreak after this element."
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53 | }
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54 | },
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55 |
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56 | create(context) {
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57 | const sourceCode = context.getSourceCode();
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58 |
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59 | //----------------------------------------------------------------------
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60 | // Helpers
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61 | //----------------------------------------------------------------------
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62 |
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63 | /**
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64 | * Normalizes a given option value.
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65 | *
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66 | * @param {string|Object|undefined} providedOption - An option value to parse.
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67 | * @returns {{multiline: boolean, minItems: number}} Normalized option object.
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68 | */
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69 | function normalizeOptionValue(providedOption) {
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70 | let consistent = false;
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71 | let multiline = false;
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72 | let minItems;
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73 |
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74 | const option = providedOption || "always";
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75 |
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76 | if (!option || option === "always" || option.minItems === 0) {
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77 | minItems = 0;
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78 | } else if (option === "never") {
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79 | minItems = Number.POSITIVE_INFINITY;
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80 | } else if (option === "consistent") {
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81 | consistent = true;
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82 | minItems = Number.POSITIVE_INFINITY;
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83 | } else {
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84 | multiline = Boolean(option.multiline);
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85 | minItems = option.minItems || Number.POSITIVE_INFINITY;
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86 | }
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87 |
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88 | return { consistent, multiline, minItems };
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89 | }
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90 |
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91 | /**
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92 | * Normalizes a given option value.
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93 | *
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94 | * @param {string|Object|undefined} options - An option value to parse.
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95 | * @returns {{ArrayExpression: {multiline: boolean, minItems: number}, ArrayPattern: {multiline: boolean, minItems: number}}} Normalized option object.
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96 | */
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97 | function normalizeOptions(options) {
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98 | const value = normalizeOptionValue(options);
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99 |
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100 | return { ArrayExpression: value, ArrayPattern: value };
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101 | }
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102 |
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103 | /**
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104 | * Reports that there shouldn't be a line break after the first token
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105 | * @param {Token} token - The token to use for the report.
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106 | * @returns {void}
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107 | */
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108 | function reportNoLineBreak(token) {
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109 | const tokenBefore = sourceCode.getTokenBefore(token, { includeComments: true });
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110 |
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111 | context.report({
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112 | loc: {
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113 | start: tokenBefore.loc.end,
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114 | end: token.loc.start
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115 | },
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116 | messageId: "unexpectedLineBreak",
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117 | fix(fixer) {
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118 | if (astUtils.isCommentToken(tokenBefore)) {
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119 | return null;
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120 | }
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121 |
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122 | if (!astUtils.isTokenOnSameLine(tokenBefore, token)) {
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123 | return fixer.replaceTextRange([tokenBefore.range[1], token.range[0]], " ");
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124 | }
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125 |
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126 | /*
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127 | * This will check if the comma is on the same line as the next element
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128 | * Following array:
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129 | * [
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130 | * 1
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131 | * , 2
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132 | * , 3
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133 | * ]
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134 | *
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135 | * will be fixed to:
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136 | * [
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137 | * 1, 2, 3
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138 | * ]
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139 | */
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140 | const twoTokensBefore = sourceCode.getTokenBefore(tokenBefore, { includeComments: true });
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141 |
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142 | if (astUtils.isCommentToken(twoTokensBefore)) {
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143 | return null;
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144 | }
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145 |
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146 | return fixer.replaceTextRange([twoTokensBefore.range[1], tokenBefore.range[0]], "");
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147 |
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148 | }
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149 | });
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150 | }
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151 |
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152 | /**
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153 | * Reports that there should be a line break after the first token
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154 | * @param {Token} token - The token to use for the report.
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155 | * @returns {void}
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156 | */
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157 | function reportRequiredLineBreak(token) {
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158 | const tokenBefore = sourceCode.getTokenBefore(token, { includeComments: true });
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159 |
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160 | context.report({
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161 | loc: {
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162 | start: tokenBefore.loc.end,
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163 | end: token.loc.start
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164 | },
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165 | messageId: "missingLineBreak",
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166 | fix(fixer) {
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167 | return fixer.replaceTextRange([tokenBefore.range[1], token.range[0]], "\n");
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168 | }
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169 | });
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170 | }
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171 |
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172 | /**
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173 | * Reports a given node if it violated this rule.
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174 | *
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175 | * @param {ASTNode} node - A node to check. This is an ObjectExpression node or an ObjectPattern node.
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176 | * @returns {void}
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177 | */
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178 | function check(node) {
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179 | const elements = node.elements;
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180 | const normalizedOptions = normalizeOptions(context.options[0]);
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181 | const options = normalizedOptions[node.type];
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182 |
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183 | let elementBreak = false;
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184 |
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185 | /*
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186 | * MULTILINE: true
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187 | * loop through every element and check
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188 | * if at least one element has linebreaks inside
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189 | * this ensures that following is not valid (due to elements are on the same line):
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190 | *
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191 | * [
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192 | * 1,
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193 | * 2,
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194 | * 3
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195 | * ]
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196 | */
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197 | if (options.multiline) {
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198 | elementBreak = elements
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199 | .filter(element => element !== null)
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200 | .some(element => element.loc.start.line !== element.loc.end.line);
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201 | }
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202 |
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203 | const linebreaksCount = node.elements.map((element, i) => {
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204 | const previousElement = elements[i - 1];
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205 |
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206 | if (i === 0 || element === null || previousElement === null) {
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207 | return false;
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208 | }
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209 |
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210 | const commaToken = sourceCode.getFirstTokenBetween(previousElement, element, astUtils.isCommaToken);
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211 | const lastTokenOfPreviousElement = sourceCode.getTokenBefore(commaToken);
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212 | const firstTokenOfCurrentElement = sourceCode.getTokenAfter(commaToken);
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213 |
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214 | return !astUtils.isTokenOnSameLine(lastTokenOfPreviousElement, firstTokenOfCurrentElement);
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215 | }).filter(isBreak => isBreak === true).length;
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216 |
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217 | const needsLinebreaks = (
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218 | elements.length >= options.minItems ||
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219 | (
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220 | options.multiline &&
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221 | elementBreak
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222 | ) ||
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223 | (
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224 | options.consistent &&
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225 | linebreaksCount > 0 &&
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226 | linebreaksCount < node.elements.length
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227 | )
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228 | );
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229 |
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230 | elements.forEach((element, i) => {
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231 | const previousElement = elements[i - 1];
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232 |
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233 | if (i === 0 || element === null || previousElement === null) {
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234 | return;
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235 | }
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236 |
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237 | const commaToken = sourceCode.getFirstTokenBetween(previousElement, element, astUtils.isCommaToken);
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238 | const lastTokenOfPreviousElement = sourceCode.getTokenBefore(commaToken);
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239 | const firstTokenOfCurrentElement = sourceCode.getTokenAfter(commaToken);
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240 |
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241 | if (needsLinebreaks) {
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242 | if (astUtils.isTokenOnSameLine(lastTokenOfPreviousElement, firstTokenOfCurrentElement)) {
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243 | reportRequiredLineBreak(firstTokenOfCurrentElement);
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244 | }
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245 | } else {
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246 | if (!astUtils.isTokenOnSameLine(lastTokenOfPreviousElement, firstTokenOfCurrentElement)) {
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247 | reportNoLineBreak(firstTokenOfCurrentElement);
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248 | }
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249 | }
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250 | });
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251 | }
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252 |
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253 | //----------------------------------------------------------------------
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254 | // Public
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255 | //----------------------------------------------------------------------
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256 |
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257 | return {
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258 | ArrayPattern: check,
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259 | ArrayExpression: check
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260 | };
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261 | }
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262 | };
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