Filter languages by whitelist and/or blacklist

lib/franc.js

@@ -127,6 +127,29 @@ function sort(a, b) {
     return a[1] - b[1];
 }
 
+/**
+ * Filter the list of languages using provided whitelist and/or blacklist
+ * @param {Object.<string, Object>} languages - Languages to filter
+ * @param {Array.<string>} whitelist - An array containing
+ *   whitelisted languages; if whitelist isn't empty
+ *   only distances for languages it includes will be calculated
+ * @param {Array.<string>} blacklist - Array containing blacklisted languages;
+ *   all blacklisted images will be removed from the languages array
+ * @return {Object.<string, Object>} - Filtered array of languages
+ */
+
+function filterLanguages(languages, whitelist, blacklist) {
+  var filteredLanguages = {};
+  for (var lang in languages) {
+    if ((whitelist.length === 0 || whitelist.indexOf(lang) >= 0) &&
+        (blacklist.indexOf(lang) < 0)) {
+      filteredLanguages[lang] = languages[lang];
+    }
+  }
+
+  return filteredLanguages;
+}
+
 /**
  * Get the distance between an array of trigram--count tuples,
  * and a language dictionary.
@@ -178,11 +201,16 @@ function getDistance(trigrams, model) {
  *   containing language--distance tuples.
  */
 
-function getDistances(trigrams, languages) {
+function getDistances(trigrams, languages, opts) {
     var distances,
+        whitelist,
+        blacklist,
         language;
 
     distances = [];
+    whitelist = opts.whitelist || [];
+    blacklist = opts.blacklist || [];
+    languages = filterLanguages(languages, whitelist, blacklist);
 
     for (language in languages) {
         distances.push([
@@ -264,8 +292,9 @@ function singleLanguageTuples(language) {
  *   containing language--distance tuples.
  */
 
-function detectAll(value) {
+function detectAll(value, opts) {
     var script;
+    opts = opts || {};
 
     if (!value || value.length < MIN_LENGTH) {
         return singleLanguageTuples('und');
@@ -292,7 +321,7 @@ function detectAll(value) {
      * Get all distances for a given script.
      */
 
-    return getDistances(utilities.asTuples(value), data[script[0]]);
+    return getDistances(utilities.asTuples(value), data[script[0]], opts);
 }
 
 /**
@@ -302,8 +331,8 @@ function detectAll(value) {
  * @return {string} The most probable language.
  */
 
-function detect(value) {
-    return detectAll(value)[0][0];
+function detect(value, opts) {
+    return detectAll(value, opts)[0][0];
 }
 
 /**