Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like ListTrait often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use ListTrait, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | trait ListTrait |
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14 | { |
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15 | /** |
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16 | * @var bool enable support `start` attribute of ordered lists. This means that lists |
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17 | * will start with the number you actually type in markdown and not the HTML generated one. |
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18 | * Defaults to `false` which means that numeration of all ordered lists(<ol>) starts with 1. |
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19 | */ |
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20 | public $keepListStartNumber = false; |
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21 | |||
22 | /** |
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23 | * identify a line as the beginning of an ordered list. |
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24 | */ |
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25 | 205 | protected function identifyOl($line) |
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26 | { |
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27 | 205 | return (($l = $line[0]) > '0' && $l <= '9' || $l === ' ') && preg_match('/^ {0,3}\d+\.[ \t]/', $line); |
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28 | } |
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29 | |||
30 | /** |
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31 | * identify a line as the beginning of an unordered list. |
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32 | */ |
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33 | 206 | protected function identifyUl($line) |
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34 | { |
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35 | 206 | $l = $line[0]; |
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36 | 206 | return ($l === '-' || $l === '+' || $l === '*') && (isset($line[1]) && (($l1 = $line[1]) === ' ' || $l1 === "\t")) || |
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37 | 206 | ($l === ' ' && preg_match('/^ {0,3}[\-\+\*][ \t]/', $line)); |
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38 | } |
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39 | |||
40 | /** |
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41 | * Consume lines for an ordered list |
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42 | */ |
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43 | 24 | View Code Duplication | protected function consumeOl($lines, $current) |
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44 | { |
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45 | // consume until newline |
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46 | |||
47 | $block = [ |
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48 | 24 | 'list', |
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49 | 'list' => 'ol', |
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50 | 'attr' => [], |
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51 | 'items' => [], |
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52 | ]; |
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53 | 24 | return $this->consumeList($lines, $current, $block, 'ol'); |
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54 | } |
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55 | |||
56 | /** |
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57 | * Consume lines for an unordered list |
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58 | */ |
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59 | 39 | View Code Duplication | protected function consumeUl($lines, $current) |
60 | { |
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61 | // consume until newline |
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62 | |||
63 | $block = [ |
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64 | 39 | 'list', |
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65 | 'list' => 'ul', |
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66 | 'items' => [], |
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67 | ]; |
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68 | 39 | return $this->consumeList($lines, $current, $block, 'ul'); |
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69 | } |
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70 | |||
71 | 46 | private function consumeList($lines, $current, $block, $type) |
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72 | { |
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73 | 46 | $item = 0; |
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74 | 46 | $indent = ''; |
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75 | 46 | $len = 0; |
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76 | 46 | $lastLineEmpty = false; |
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77 | // track the indentation of list markers, if indented more than previous element |
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78 | // a list marker is considered to be long to a lower level |
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79 | 46 | $leadSpace = 3; |
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80 | 46 | $marker = $type === 'ul' ? ltrim($lines[$current])[0] : ''; |
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81 | 46 | for ($i = $current, $count = count($lines); $i < $count; $i++) { |
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82 | 46 | $line = $lines[$i]; |
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83 | // match list marker on the beginning of the line |
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84 | 46 | $pattern = ($type === 'ol') ? '/^( {0,'.$leadSpace.'})(\d+)\.[ \t]+/' : '/^( {0,'.$leadSpace.'})\\'.$marker.'[ \t]+/'; |
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85 | 46 | if (preg_match($pattern, $line, $matches)) { |
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86 | 46 | if (($len = substr_count($matches[0], "\t")) > 0) { |
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87 | 10 | $indent = str_repeat("\t", $len); |
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88 | 10 | $line = substr($line, strlen($matches[0])); |
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89 | } else { |
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90 | 43 | $len = strlen($matches[0]); |
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91 | 43 | $indent = str_repeat(' ', $len); |
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92 | 43 | $line = substr($line, $len); |
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93 | } |
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94 | 46 | if ($i === $current) { |
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95 | 46 | $leadSpace = strlen($matches[1]) + 1; |
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96 | } |
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97 | |||
98 | 46 | if ($type === 'ol' && $this->keepListStartNumber) { |
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99 | // attr `start` for ol |
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100 | 2 | if (!isset($block['attr']['start']) && isset($matches[2])) { |
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101 | 2 | $block['attr']['start'] = $matches[2]; |
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102 | } |
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103 | } |
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104 | |||
105 | 46 | $block['items'][++$item][] = $line; |
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106 | 46 | $block['lazyItems'][$item] = $lastLineEmpty; |
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107 | 46 | $lastLineEmpty = false; |
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108 | 40 | } elseif (ltrim($line) === '') { |
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109 | // line is empty, may be a lazy list |
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110 | 40 | $lastLineEmpty = true; |
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111 | |||
112 | // two empty lines will end the list |
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113 | 40 | if (!isset($lines[$i + 1][0])) { |
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114 | 25 | break; |
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115 | |||
116 | // next item is the continuation of this list -> lazy list |
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117 | 40 | } elseif (preg_match($pattern, $lines[$i + 1])) { |
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118 | 18 | $block['items'][$item][] = $line; |
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119 | 18 | $block['lazyItems'][$item] = true; |
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120 | |||
121 | // next item is indented as much as this list -> lazy list if it is not a reference |
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122 | 37 | } elseif (strncmp($lines[$i + 1], $indent, $len) === 0 || !empty($lines[$i + 1]) && $lines[$i + 1][0] == "\t") { |
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123 | 20 | $block['items'][$item][] = $line; |
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124 | 20 | $nextLine = $lines[$i + 1][0] === "\t" ? substr($lines[$i + 1], 1) : substr($lines[$i + 1], $len); |
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125 | 20 | $block['lazyItems'][$item] = empty($nextLine) || !method_exists($this, 'identifyReference') || !$this->identifyReference($nextLine); |
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126 | |||
127 | // everything else ends the list |
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128 | } else { |
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129 | 40 | break; |
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130 | } |
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131 | } else { |
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132 | 30 | if ($line[0] === "\t") { |
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133 | 7 | $line = substr($line, 1); |
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134 | 26 | } elseif (strncmp($line, $indent, $len) === 0) { |
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135 | 23 | $line = substr($line, $len); |
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136 | } |
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137 | 30 | $block['items'][$item][] = $line; |
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138 | 30 | $lastLineEmpty = false; |
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139 | } |
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140 | |||
141 | // if next line is <hr>, end the list |
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142 | 46 | if (!empty($lines[$i + 1]) && method_exists($this, 'identifyHr') && $this->identifyHr($lines[$i + 1])) { |
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143 | 3 | break; |
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144 | } |
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145 | } |
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146 | |||
147 | 46 | foreach($block['items'] as $itemId => $itemLines) { |
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148 | 46 | $content = []; |
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149 | 46 | if (!$block['lazyItems'][$itemId]) { |
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150 | 41 | $firstPar = []; |
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151 | 41 | while (!empty($itemLines) && rtrim($itemLines[0]) !== '' && $this->detectLineType($itemLines, 0) === 'paragraph') { |
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152 | 41 | $firstPar[] = array_shift($itemLines); |
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153 | } |
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154 | 41 | $content = $this->parseInline(implode("\n", $firstPar)); |
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155 | } |
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156 | 46 | if (!empty($itemLines)) { |
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157 | 30 | $content = array_merge($content, $this->parseBlocks($itemLines)); |
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158 | } |
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159 | 46 | $block['items'][$itemId] = $content; |
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160 | } |
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161 | |||
162 | 46 | return [$block, $i]; |
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163 | } |
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164 | |||
165 | /** |
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166 | * Renders a list |
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167 | */ |
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168 | 46 | protected function renderList($block) |
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169 | { |
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170 | 46 | $type = $block['list']; |
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171 | |||
172 | 46 | if (!empty($block['attr'])) { |
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173 | 2 | $output = "<$type " . $this->generateHtmlAttributes($block['attr']) . ">\n"; |
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174 | } else { |
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175 | 45 | $output = "<$type>\n"; |
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176 | } |
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177 | |||
178 | 46 | foreach ($block['items'] as $item => $itemLines) { |
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179 | 46 | $output .= '<li>' . $this->renderAbsy($itemLines). "</li>\n"; |
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180 | } |
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181 | 46 | return $output . "</$type>\n"; |
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182 | } |
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183 | |||
184 | |||
185 | /** |
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186 | * Return html attributes string from [attrName => attrValue] list |
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187 | * @param array $attributes the attribute name-value pairs. |
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188 | * @return string |
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189 | */ |
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190 | 2 | private function generateHtmlAttributes($attributes) |
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191 | { |
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192 | 2 | foreach ($attributes as $name => $value) { |
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193 | 2 | $attributes[$name] = "$name=\"$value\""; |
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194 | } |
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195 | 2 | return implode(' ', $attributes); |
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196 | } |
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197 | |||
198 | abstract protected function parseBlocks($lines); |
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202 | } |
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203 |
Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation.
You can also find more detailed suggestions in the “Code” section of your repository.