Improve output of book.log

lib/book.js

@@ -3,6 +3,7 @@ var _ = require("lodash");
 var path = require("path");
 var lunr = require('lunr');
 var parsers = require("gitbook-parsers");
+var color = require('bash-color');
 
 var fs = require("./utils/fs");
 var parseNavigation = require("./utils/navigation");
@@ -86,6 +87,13 @@ Book.LOG_LEVELS = {
 	ERROR: 3,
 	DISABLED: 10
 };
+Book.LOG_COLORS = {
+	DEBUG: color.purple,
+	INFO: color.cyan,
+	WARNING: color.yellow,
+	ERROR: color.red,
+	DISABLED: 10
+};
 
 // Initialize and parse the book: config, summary, glossary
 Book.prototype.parse = function() {
@@ -573,7 +581,9 @@ Book.prototype.log = function(level) {
 	if (level < this.context.logLevel) return;
 
 	var args = Array.prototype.slice.apply(arguments);
-	args[0] = _.findKey(Book.LOG_LEVELS, function(v) { return v == args[0]; }).toLowerCase()+":";
+	var levelKey = _.findKey(Book.LOG_LEVELS, function(v) { return v == args[0]; });
+
+	args[0] = Book.LOG_COLORS[levelKey](levelKey.toLowerCase()+":");
 	this.context.log.apply(null, args);
 };
 Book.prototype.logDebug = _.partial(Book.prototype.log, Book.LOG_LEVELS.DEBUG);