Rewrite cld to actually be async with a promise API

README.md

@@ -19,27 +19,53 @@ Linux users, make sure you have g++ >= 4.8. If this is not an option, you should
 ## Examples
 ### Simple
 ```js
-require('cld').detect('This is a language recognition example', function(err, result) {
+const cld = require('cld');
+
+// As a promise
+cld.detect('This is a language recognition example').then((result) => {
   console.log(result);
 });
+
+// In an async function
+async function testCld() {
+  const result = await cld.detect('This is a language recognition example');
+  console.log(result);
+}
 ```
 
 ### Advanced
 ```js
-var text    = 'Това е пример за разпознаване на Български език';
-var options = {
+const cld = require('cld');
+const text     = 'Това е пример за разпознаване на Български език';
+const options  = {
   isHTML       : false,
   languageHint : 'BULGARIAN',
   encodingHint : 'ISO_8859_5',
   tldHint      : 'bg',
   httpHint     : 'bg'
 };
 
-require('cld').detect(text, options, function(err, result) {
+// As a promise
+cld.detect(text, options).then((result) => {
   console.log(result);
 });
+
+// In an async function
+async function testCld() {
+  const result = await cld.detect(text, options);
+  console.log(result);
+}
 ```
 
+### Legacy
+Detect can be called leveraging the node callback pattern. If options are provided, the third parameter should be the callback.
+```javascript
+const cld = require('cld');
+
+cld.detect('This is a language recognition example', (err, result) => {
+  console.log(result);
+});
+```
 
 ## Options
 

index.js

@@ -1,76 +1,87 @@
-var _    = require('underscore');
-var cld2 = require('./build/Release/cld');
+const _    = require('underscore');
+const cld2 = require('./build/Release/cld');
 
 module.exports = {
   LANGUAGES          : cld2.LANGUAGES,
   DETECTED_LANGUAGES : cld2.DETECTED_LANGUAGES,
   ENCODINGS          : cld2.ENCODINGS,
 
-  detect : function (text, options, cb) {
-    if (arguments.length < 2) {
-      return;
-    }
-    if (arguments.length < 3) {
+  async detect(text, options) {
+    let cb = arguments[2];
+    if (typeof cb !== 'function' && typeof options === 'function') {
       cb = options;
       options = {};
     }
-    if (!_.isFunction(cb)) {
-      return;
-    }
 
-    if (!_.isString(text) || text.length < 1) {
-      return cb({message:'Empty or invalid text'});
-    }
+    try {
+      if (arguments.length < 1) {
+        throw new Error('Not enough arguments provided');
+      }
 
-    var defaults = {
-      isHTML       : false,
-      languageHint : '',
-      encodingHint : '',
-      tldHint      : '',
-      httpHint     : ''
-    };
-    options = _.defaults(options, defaults);
+      if (!_.isString(text) || text.length < 1) {
+        throw new Error('Empty or invalid text');
+      }
 
-    if (!_.isBoolean(options.isHTML)) {
-      return cb({message:'Invalid isHTML value'});
-    }
-    if (!_.isString(options.languageHint)) {
-      return cb({message:'Invalid languageHint'});
-    }
-    if (!_.isString(options.encodingHint)) {
-      return cb({message:'Invalid encodingHint'});
-    }
-    if (!_.isString(options.tldHint)) {
-      return cb({message:'Invalid tldHint'});
-    }
-    if (!_.isString(options.httpHint)) {
-      return cb({message:'Invalid httpHint'});
-    }
-    if (options.encodingHint.length > 0 &&
-      !~cld2.ENCODINGS.indexOf(options.encodingHint)) {
+      const defaults = {
+        isHTML       : false,
+        languageHint : '',
+        encodingHint : '',
+        tldHint      : '',
+        httpHint     : ''
+      };
+      options = _.defaults(options, defaults);
 
-      return cb({message:'Invalid encodingHint, see ENCODINGS'});
-    }
-    if (options.languageHint.length > 0 &&
-      !~_.keys(cld2.LANGUAGES).indexOf(options.languageHint) &&
-      !~_.values(cld2.LANGUAGES).indexOf(options.languageHint)) {
+      if (!_.isBoolean(options.isHTML)) {
+        throw new Error('Invalid isHTML value');
+      }
+      if (!_.isString(options.languageHint)) {
+        throw new Error('Invalid languageHint');
+      }
+      if (!_.isString(options.encodingHint)) {
+        throw new Error('Invalid encodingHint');
+      }
+      if (!_.isString(options.tldHint)) {
+        throw new Error('Invalid tldHint');
+      }
+      if (!_.isString(options.httpHint)) {
+        throw new Error('Invalid httpHint');
+      }
+      if (options.encodingHint.length > 0 &&
+        !~cld2.ENCODINGS.indexOf(options.encodingHint)) {
 
-      return cb({message:'Invalid languageHint, see LANGUAGES'});
-    }
+        throw new Error('Invalid encodingHint, see ENCODINGS');
+      }
+      if (options.languageHint.length > 0 &&
+        !~_.keys(cld2.LANGUAGES).indexOf(options.languageHint) &&
+        !~_.values(cld2.LANGUAGES).indexOf(options.languageHint)) {
 
-    var result = cld2.detect(
-      text,
-      !options.isHTML,
-      options.languageHint,
-      options.encodingHint,
-      options.tldHint,
-      options.httpHint
-    );
+        throw new Error('Invalid languageHint, see LANGUAGES');
+      }
 
-    if (result.languages.length < 1) {
-      return cb({message:'Failed to identify language'});
-    }
+      const result = await cld2.detectAsync(
+        text,
+        !options.isHTML,
+        options.languageHint,
+        options.encodingHint,
+        options.tldHint,
+        options.httpHint
+      );
+
+      if (result.languages.length < 1) {
+        throw new Error('Failed to identify language');
+      }
 
-    return cb(null, result);
+      if (cb) {
+        return cb(null, result);
+      } else {
+        return result;
+      }
+    } catch (error) {
+      if (cb) {
+        cb(error);
+      } else {
+        throw error;
+      }
+    }
   }
 };