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