1 module.exports = preferredLanguages;
2 preferredLanguages.preferredLanguages = preferredLanguages;
4 function parseAcceptLanguage(accept) {
5 var accepts = accept.split(',');
7 for (var i = 0, j = 0; i < accepts.length; i++) {
8 var langauge = parseLanguage(accepts[i].trim(), i);
11 accepts[j++] = langauge;
21 function parseLanguage(s, i) {
22 var match = s.match(/^\s*(\S+?)(?:-(\S+?))?\s*(?:;(.*))?$/);
23 if (!match) return null;
25 var prefix = match[1],
29 if (suffix) full += "-" + suffix;
33 var params = match[3].split(';')
34 for (var i = 0; i < params.length; i ++) {
35 var p = params[i].split('=');
36 if (p[0] === 'q') q = parseFloat(p[1]);
49 function getLanguagePriority(language, accepted, index) {
50 var priority = {o: -1, q: 0, s: 0};
52 for (var i = 0; i < accepted.length; i++) {
53 var spec = specify(language, accepted[i], index);
55 if (spec && (priority.s - spec.s || priority.q - spec.q || priority.o - spec.o) < 0) {
63 function specify(language, spec, index) {
64 var p = parseLanguage(language)
67 if(spec.full.toLowerCase() === p.full.toLowerCase()){
69 } else if (spec.prefix.toLowerCase() === p.full.toLowerCase()) {
71 } else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
73 } else if (spec.full !== '*' ) {
85 function preferredLanguages(accept, provided) {
86 // RFC 2616 sec 14.4: no header = *
87 var accepts = parseAcceptLanguage(accept === undefined ? '*' : accept || '');
90 // sorted list of all languages
91 return accepts.filter(isQuality).sort(compareSpecs).map(function getLanguage(spec) {
96 var priorities = provided.map(function getPriority(type, index) {
97 return getLanguagePriority(type, accepts, index);
100 // sorted list of accepted languages
101 return priorities.filter(isQuality).sort(compareSpecs).map(function getLanguage(priority) {
102 return provided[priorities.indexOf(priority)];
106 function compareSpecs(a, b) {
107 return (b.q - a.q) || (b.s - a.s) || (a.o - b.o) || (a.i - b.i) || 0;
110 function isQuality(spec) {