Rewrite code to ES6 syntax

.eslintrc

@@ -12,5 +12,8 @@
     "env": {
         "node": true
     },
+    "parserOptions": {
+        "ecmaVersion": 8
+    },
     "extends": "eslint:recommended"
 }

build/build.js

@@ -1,79 +1,66 @@
-var async = require('async');
-var fs = require('fs');
-var path = require('path');
+const fs = require('fs');
+const path = require('path');
 
 // File paths
-var EMOJI_PATH = path.resolve(__dirname, 'Emoji_Sentiment_Data_v1.0.csv');
-var RESULT_PATH = path.resolve(__dirname, 'emoji.json');
+const EMOJI_PATH = path.resolve(__dirname, 'Emoji_Sentiment_Data_v1.0.csv');
+const RESULT_PATH = path.resolve(__dirname, 'emoji.json');
 
 /**
- * Read emoji data from original format (CSV).
- * @param  {object}   hash     Result hash
- * @param  {Function} callback Callback
- * @return {void}
+ * Reads emoji data from original format (CSV).
+ * @param  {object}   hash     Result hash.
+ * @return {object}   hash     Result hash.
  */
-function processEmoji(hash, callback) {
+const processEmoji = async () => {
+    let hash = {};
     // Read file
-    fs.readFile(EMOJI_PATH, 'utf8', function (err, data) {
-        if (err) return callback(err);
-
-        // Split data by new line
-        data = data.split(/\n/);
-
-        // Iterate over dataset and add to hash
-        for (var i in data) {
-            var line = data[i].split(',');
-
-            // Validate line
-            if (i == 0) continue;               // Label
-            if (line.length !== 9) continue;    // Invalid
+    const data = await fs.readFileSync(EMOJI_PATH, 'utf8');
+    // Split data by new line
+    const lines = data.split(/\n/);
+    // Iterate over dataset and add to hash
+    for (const i in lines) {
+        const line = lines[i].split(',');
+        // Validate line
+        if (i === '0' || i === 0 || line.length !== 9) continue;
+        //  ^ Label     ^ Label    ^ Invalid
 
-            // Establish sentiment value
-            var emoji = String.fromCodePoint(line[1]);
-            var occurences = line[2];
-            var negCount = line[4];
-            var posCount = line[6];
-            var score = (posCount / occurences) - (negCount / occurences);
-            var sentiment = Math.floor(5 * score);
+        // Establish sentiment value
+        const emoji = String.fromCodePoint(line[1]);
+        const occurences = line[2];
+        const negCount = line[4];
+        const posCount = line[6];
+        const score = posCount / occurences - negCount / occurences;
+        const sentiment = Math.floor(5 * score);
 
-            // Validate score
-            if (Number.isNaN(sentiment)) continue;
-            if (sentiment === 0) continue;
+        // Validate score
+        if (Number.isNaN(sentiment) || sentiment === 0) continue;
 
-            // Add to hash
-            hash[emoji] = sentiment;
-        }
-
-        callback(null, hash);
-    });
-}
+        // Add to hash
+        hash[emoji] = sentiment;
+    }
+    return hash;
+};
 
 /**
- * Write sentiment score hash to disk.
+ * Writes sentiment score hash to disk.
  * @param  {object}   hash     Result hash
- * @param  {Function} callback Callback
- * @return {void}
+ * @return {object}   hash     Result hash
  */
-function finish(hash, callback) {
-    var result = JSON.stringify(hash, null, 4);
-    fs.writeFile(RESULT_PATH, result, function (err) {
-        if (err) return callback(err);
-        callback(null, hash);
-    });
-}
+const writeJSON = async hash => {
+    const result = JSON.stringify(hash, null, 4);
+    await fs.writeFileSync(RESULT_PATH, result);
+    process.stdout.write(`Complete: ${Object.keys(hash).length} entries.\n`);
+};
 
-// Execute build process
-async.waterfall([
-    function (cb) {
-        cb(null, {});
-    },
-    processEmoji,
-    finish
-], function(err, result) {
-    if (err) throw new Error(err);
-    process.stderr.write(
-        'Complete: ' +
-        Object.keys(result).length +
-        ' entries.\n'
-    );
-});
+/**
+ * Executes build process.
+ * @return {undefined}
+ */
+const build = async () => {
+    try {
+        const hash = await processEmoji();
+        writeJSON(hash);
+    } catch (e) {
+        process.stderr.write(`${e.toString()}\n`);
+    }
+};
+build();

languages/en/index.js

@@ -1,4 +1,7 @@
+const labels = require('./labels.json');
+const scoringStrategy = require('./scoring-strategy');
+
 module.exports = {
-    labels: require('./labels.json'),
-    scoringStrategy: require('./scoring-strategy')
+    labels,
+    scoringStrategy
 };

languages/en/scoring-strategy.js

@@ -1,13 +1,15 @@
-var negators = require('./negators.json');
+const negators = require('./negators.json');
 
-module.exports = {
-    apply: function(tokens, cursor, tokenScore) {
-        if (cursor > 0) {
-            var prevtoken = tokens[cursor - 1];
-            if (negators[prevtoken]) {
-                tokenScore = -tokenScore;
-            }
+const apply = (tokens, cursor, tokenScore) => {
+    if (cursor > 0) {
+        const prevtoken = tokens[cursor - 1];
+        if (negators[prevtoken]) {
+            tokenScore = -tokenScore;
         }
-        return tokenScore;
     }
+    return tokenScore;
+};
+
+module.exports = {
+    apply
 };

lib/index.js

@@ -1,98 +1,97 @@
-var tokenize = require('./tokenize');
-var languageProcessor = require('./language-processor');
+const tokenize = require('./tokenize');
+const languageProcessor = require('./language-processor');
 
-/**
- * Constructor
- * @param {Object} options - Instance options
- */
-var Sentiment = function (options) {
-    this.options = options;
-};
-
-/**
- * Registers the specified language
- *
- * @param {String} languageCode
- *     - Two-digit code for the language to register
- * @param {Object} language
- *     - The language module to register
- */
-Sentiment.prototype.registerLanguage = function (languageCode, language) {
-    languageProcessor.addLanguage(languageCode, language);
-};
-
-/**
- * Performs sentiment analysis on the provided input 'phrase'.
- *
- * @param {String} phrase
- *     - Input phrase
- * @param {Object} opts
- *     - Options
- * @param {Object} opts.language
- *     - Input language code (2 digit code), defaults to 'en'
- * @param {Object} opts.extras
- *     - Optional sentiment additions to AFINN (hash k/v pairs)
- * @param {function} callback
- *     - Optional callback
- * @return {Object}
- */
-Sentiment.prototype.analyze = function (phrase, opts, callback) {
-    // Parse arguments
-    if (typeof phrase === 'undefined') phrase = '';
-    if (typeof opts === 'function') {
-        callback = opts;
-        opts = {};
+class Sentiment {
+    /**
+     * Represents a Sentiment.
+     * @constructor
+     * @param {Object} options - Instance options.
+     */
+    constructor(options) {
+        this.options = options;
     }
-    opts = opts || {};
-
-    var languageCode = opts.language || 'en';
-    var labels = languageProcessor.getLabels(languageCode);
-
-    // Merge extra labels
-    if (typeof opts.extras === 'object') {
-        labels = Object.assign(labels, opts.extras);
+    /**
+     * Registers the specified language.
+     * @param {string} languageCode - Two-digit code for the language to
+     *                              register.
+     * @param {object} language - The language module to register.
+     */
+    registerLanguage(languageCode, language) {
+        languageProcessor.addLanguage(languageCode, language);
     }
+    /**
+     * Performs sentiment analysis on the provided input 'phrase'.
+     * @param {string} phrase - Input phrase
+     * @param {object} opts - Options
+     * @param {object} opts.language - Input language code (2 digit code),
+     *                               defaults to 'en'
+     * @param {object} opts.extras - Optional sentiment additions to AFINN
+     *                             (hash k/v pairs)
+     * @param {function} callback - Optional callback
+     * @return {object}
+     */
+    analyze(phrase = '', opts = { language: 'en' }, callback) {
+        // Storage objects
+        const tokens = tokenize(phrase);
+        let score = 0;
+        let words = [];
+        let positive = [];
+        let negative = [];
 
-    // Storage objects
-    var tokens      = tokenize(phrase),
-        score       = 0,
-        words       = [],
-        positive    = [],
-        negative    = [];
+        // Parse arguments
+        if (typeof opts === 'function') {
+            callback = opts;
+            opts = {};
+        }
 
-    // Iterate over tokens
-    var i = tokens.length;
-    while (i--) {
-        var obj = tokens[i];
-        if (!labels.hasOwnProperty(obj)) continue;
-        words.push(obj);
+        const languageCode = opts.language;
+        let labels = languageProcessor.getLabels(languageCode);
 
-        // Apply scoring strategy
-        var tokenScore = labels[obj];
-        // eslint-disable-next-line max-len
-        tokenScore = languageProcessor.applyScoringStrategy(languageCode, tokens, i, tokenScore);
-        if (tokenScore > 0) positive.push(obj);
-        if (tokenScore < 0) negative.push(obj);
-        score += tokenScore;
-    }
+        // Merge extra labels
+        if (typeof opts.extras === 'object') {
+            labels = Object.assign(labels, opts.extras);
+        }
+
+        // Iterate over tokens
+        let i = tokens.length;
+        while (i--) {
+            const obj = tokens[i];
+            if (!labels.hasOwnProperty(obj)) continue;
+            words = words.concat(obj);
+            // Apply scoring strategy
+            const tokenScore = languageProcessor.applyScoringStrategy(
+                languageCode,
+                tokens,
+                i,
+                labels[obj]
+            );
+            if (tokenScore > 0) {
+                positive = positive.concat(obj);
+            }
+            if (tokenScore < 0) {
+                negative = negative.concat(obj);
+            }
+            score += tokenScore;
+        }
 
-    var result = {
-        score:          score,
-        comparative:    tokens.length > 0 ? score / tokens.length : 0,
-        tokens:         tokens,
-        words:          words,
-        positive:       positive,
-        negative:       negative
-    };
+        const result = {
+            score,
+            comparative: tokens.length > 0 ? score / tokens.length : 0,
+            tokens,
+            words,
+            positive,
+            negative
+        };
 
-    // Handle optional async interface
-    if (typeof callback === 'function') {
-        process.nextTick(function () {
-            callback(null, result);
-        });
-    } else {
-        return result;
+        // Handle optional async interface
+        if (typeof callback === 'function') {
+            process.nextTick(() => {
+                callback(null, result);
+            });
+        } else {
+            return result;
+        }
     }
-};
+}
 
 module.exports = Sentiment;