Basic progress bars support added

lib/progress.js

@@ -0,0 +1,109 @@
+'use strict';
+
+/**
+ * Progress bar class
+ **/
+function ProgressBar(maxValue) {
+
+	var self = this;
+	self.value = 0;
+	self.MAX_VALUE = maxValue || 100;
+	self.startTime = Date.now();
+
+	/**
+	 * Transforms a number of seconds into an string representing the
+	 * hours, minutes and seconds in format HH:MM:SS
+	 **/
+	function secondsToTimeString(seconds) {
+		var minutes = 0, hours = 0;
+		if (seconds / 60 > 0) {
+			minutes = parseInt(seconds / 60, 10);
+			seconds = seconds % 60;
+		}
+		if (minutes / 60 > 0) {
+			hours = parseInt(minutes / 60, 10);
+			minutes = minutes % 60;
+		}
+		return ('0' + hours).slice(-2) + ':' + ('0' + minutes).slice(-2) + ':' + ('0' + seconds).slice(-2);
+	}
+
+	/**
+	 * Computes the amount of seconds from the begining of the progress
+	 **/
+	self.getEllapsedTime = function () {
+		return parseInt((Date.now() - self.startTime) / 1000, 10);
+	};
+
+	/**
+	 * Computes the estimated remaining time in seconds
+	 **/
+	self.getRemainingTime = (function () {
+		var lastRemainingTimes = [];
+		return function () {
+			var secondsPerTick = self.getEllapsedTime() / self.value;
+			var remaining = parseInt((self.MAX_VALUE - self.value) * secondsPerTick, 10);
+			lastRemainingTimes.push(remaining);
+			if (lastRemainingTimes.length > 5) {
+				lastRemainingTimes.shift();
+			}
+			return parseInt(lastRemainingTimes.reduce(function (acum, item) {
+				return acum + item;
+			}, 0) / lastRemainingTimes.length, 10);
+		};
+	}());
+
+	/**
+	 * Sets the current value of the progress bar.
+	 * It must be a number between 0 and the MAX_VALUE of the bar
+	 **/
+	self.setValue = function (value) {
+		self.value = value;
+		self.print();
+		if (self.value >= self.MAX_VALUE && self.finishedCallback) {
+			process.stdout.write('\n');
+			self.finishedCallback();
+		}
+	};
+
+	/**
+	 * Replaces the previous bar print with the current one, updating the status
+	 **/
+	self.print = function () {
+
+		var ellapsedTime = secondsToTimeString(self.getEllapsedTime());
+		var percent = parseInt(self.value * 100 / self.MAX_VALUE, 10);
+		var prefix = ellapsedTime + ' ' + percent + '%';
+
+		var eta = secondsToTimeString(self.getRemainingTime());
+		var sufix = 'ETA ' + eta;
+
+		process.stdout.write('\r');
+		var TERMINAL_WIDTH = process.stdout.width || 70;
+		var ticks = [];
+
+		for (var i = 0, len = (TERMINAL_WIDTH - ellapsedTime.length - 3); i < len; i++) {
+			if ((i * 100 / len) <= percent) {
+				ticks.push('#');
+			} else {
+				ticks.push('·');
+			}
+		}
+
+		process.stdout.write(prefix + ' [' + ticks.join('') + '] ' + sufix);
+	};
+
+	/**
+	 * Receives a function to call when progress finishes
+	 **/
+	self.onFinish = function (callback) {
+		self.finishedCallback = callback;
+	};
+
+}
+
+// Exports
+
+exports.progressBar = function (max) {
+	var p = new ProgressBar(max);
+	return p;
+};

main.js

@@ -21,3 +21,7 @@ exports.question = require('./lib/question.js').question;
 var reading = require('./lib/reading.js');
 exports.read = reading.read;
 exports.readByLines = reading.readByLines;
+
+// Progress bar
+var progress = require('./lib/progress.js');
+exports.progressBar = progress.progressBar;