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9 | 'use strict';
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10 |
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15 |
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16 | module.exports = preferredLanguages;
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17 | module.exports.preferredLanguages = preferredLanguages;
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18 |
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19 |
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20 |
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21 |
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22 |
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23 |
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24 | var simpleLanguageRegExp = /^\s*([^\s\-;]+)(?:-([^\s;]+))?\s*(?:;(.*))?$/;
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25 |
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26 |
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27 |
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28 |
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29 |
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30 |
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31 | function parseAcceptLanguage(accept) {
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32 | var accepts = accept.split(',');
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33 |
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34 | for (var i = 0, j = 0; i < accepts.length; i++) {
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35 | var language = parseLanguage(accepts[i].trim(), i);
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36 |
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37 | if (language) {
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38 | accepts[j++] = language;
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39 | }
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40 | }
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41 |
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42 |
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43 | accepts.length = j;
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44 |
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45 | return accepts;
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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 |
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51 |
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52 |
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53 | function parseLanguage(str, i) {
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54 | var match = simpleLanguageRegExp.exec(str);
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55 | if (!match) return null;
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56 |
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57 | var prefix = match[1],
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58 | suffix = match[2],
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59 | full = prefix;
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60 |
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61 | if (suffix) full += "-" + suffix;
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62 |
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63 | var q = 1;
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64 | if (match[3]) {
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65 | var params = match[3].split(';')
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66 | for (var j = 0; j < params.length; j++) {
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67 | var p = params[j].split('=');
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68 | if (p[0] === 'q') q = parseFloat(p[1]);
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69 | }
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70 | }
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71 |
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72 | return {
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73 | prefix: prefix,
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74 | suffix: suffix,
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75 | q: q,
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76 | i: i,
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77 | full: full
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78 | };
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79 | }
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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 |
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85 |
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86 | function getLanguagePriority(language, accepted, index) {
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87 | var priority = {o: -1, q: 0, s: 0};
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88 |
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89 | for (var i = 0; i < accepted.length; i++) {
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90 | var spec = specify(language, accepted[i], index);
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91 |
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92 | if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
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93 | priority = spec;
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94 | }
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95 | }
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96 |
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97 | return priority;
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98 | }
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99 |
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100 |
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101 |
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102 |
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103 |
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104 |
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105 | function specify(language, spec, index) {
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106 | var p = parseLanguage(language)
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107 | if (!p) return null;
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108 | var s = 0;
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109 | if(spec.full.toLowerCase() === p.full.toLowerCase()){
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110 | s |= 4;
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111 | } else if (spec.prefix.toLowerCase() === p.full.toLowerCase()) {
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112 | s |= 2;
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113 | } else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
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114 | s |= 1;
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115 | } else if (spec.full !== '*' ) {
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116 | return null
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117 | }
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118 |
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119 | return {
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120 | i: index,
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121 | o: spec.i,
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122 | q: spec.q,
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123 | s: s
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124 | }
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125 | };
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126 |
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127 |
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128 |
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129 |
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130 |
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131 |
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132 | function preferredLanguages(accept, provided) {
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133 |
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134 | var accepts = parseAcceptLanguage(accept === undefined ? '*' : accept || '');
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135 |
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136 | if (!provided) {
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137 |
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138 | return accepts
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139 | .filter(isQuality)
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140 | .sort(compareSpecs)
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141 | .map(getFullLanguage);
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142 | }
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143 |
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144 | var priorities = provided.map(function getPriority(type, index) {
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145 | return getLanguagePriority(type, accepts, index);
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146 | });
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147 |
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148 |
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149 | return priorities.filter(isQuality).sort(compareSpecs).map(function getLanguage(priority) {
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150 | return provided[priorities.indexOf(priority)];
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151 | });
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152 | }
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153 |
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154 |
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155 |
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156 |
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157 |
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158 |
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159 | function compareSpecs(a, b) {
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160 | return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
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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 |
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166 |
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167 |
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168 | function getFullLanguage(spec) {
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169 | return spec.full;
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170 | }
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171 |
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172 |
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173 |
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174 |
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175 |
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176 |
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177 | function isQuality(spec) {
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178 | return spec.q > 0;
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179 | }
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