From 2e8109ef904a2f00e3696ca0d639f2c152e9324d Mon Sep 17 00:00:00 2001
From: Rodrigo Bermudez Schettino <rodrigobermudezschettino@gmail.com>
Date: Wed, 24 Apr 2019 01:23:25 +0800
Subject: [PATCH] Improve logging after optimization

---
 changelog.md | 13 ++++++++++++-
 index.js     | 22 ++++++++++++----------
 package.json |  1 +
 readme.md    |  9 +++------
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/changelog.md b/changelog.md
index bb3576c..898918c 100644
--- a/changelog.md
+++ b/changelog.md
@@ -16,6 +16,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.1.0] - 2019-04-24
+
+### Added
+
+- Log percentage difference instead of file size in bytes.
+
+### Fixed
+
+- Made error logging more robust.
+
 ## [1.0.1] - 2019-04-23
 
 ### Fixed
@@ -29,6 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Optimize file size of PDFs
 
-[unreleased]: https://github.com/rodrigobdz/pdfoptim/compare/v1.0.1...HEAD
+[unreleased]: https://github.com/rodrigobdz/pdfoptim/compare/v1.1.0...HEAD
+[v1.0.1]: https://github.com/rodrigobdz/pdfoptim/compare/v1.0.1...v1.1.0
 [v1.0.1]: https://github.com/rodrigobdz/pdfoptim/compare/v1.0.0...v1.0.1
 [v1.0.0]: https://github.com/rodrigobdz/pdfoptim/compare/b30480643d7a74ff1f383674a0f48c735fe73faa...v1.0.0
diff --git a/index.js b/index.js
index b8b5eaf..86028e5 100644
--- a/index.js
+++ b/index.js
@@ -2,23 +2,23 @@
 const fs = require('fs');
 const path = require('path');
 const {execSync} = require('child_process');
+const percentageDiff = require('percentage-diff');
 
 /**
- * Calculate file size and return human readable representation
+ * Get filesize in bytes
  * @param {string} file Path to file
  *
- * @returns {string} '<size> bytes'
+ * @returns {string} Size in bytes
  */
-function humanFileSize(file) {
-	return `${fs.statSync(file).size} bytes`;
+function fileSizeInBytes(file) {
+	return Number(fs.statSync(file).size);
 }
 
 function logOptimizationResults(oldSize, file, outputFile) {
-	const newSize = humanFileSize(outputFile);
+	const newSize = fileSizeInBytes(outputFile);
+	const diff = percentageDiff(oldSize, newSize);
 
-	console.log('File Size Comparison');
-	console.log(`Original: ${oldSize}`);
-	console.log(`Optimized: ${newSize}\n`);
+	console.log(`Filesize difference ${percentageDiff.toPercentage(diff)} ✂️`);
 	console.log(`Optimized version of ${path.basename(file)} saved as ${outputFile} 🎉`);
 }
 
@@ -41,13 +41,15 @@ module.exports = (file, options = {}) => {
 		return false;
 	}
 
-	const oldSize = humanFileSize(file);
+	const oldSize = fileSizeInBytes(file);
 
 	try {
 		execSync(`\\gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=${options.outputFile} ${file}`);
 		logOptimizationResults(oldSize, file, options.outputFile);
 	} catch (error) {
-		console.log(error.stdout.toString());
+		const errMsg = error.stdout ? error.stdout : error;
+		console.log(errMsg.toString());
+
 		return false;
 	}
 
diff --git a/package.json b/package.json
index b1e3e82..be72f09 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
 	],
 	"dependencies": {
 		"meow": "^5.0.0",
+		"percentage-diff": "^1.1.0",
 		"update-notifier": "^2.5.0"
 	},
 	"devDependencies": {
diff --git a/readme.md b/readme.md
index 535bd67..4b44a95 100644
--- a/readme.md
+++ b/readme.md
@@ -14,12 +14,8 @@ $ npm install pdfoptim
 const pdfoptim = require('pdfoptim');
 
 pdfoptim('printer-manual.pdf');
-// File Size Comparison
-// Original: 3595210 bytes
-// Optimized: 738584 bytes
-
-// Optimized version of printer-manual.pdf
-// saved as optimized-1556032400471.pdf 🎉
+// Filesize difference -79.46% ✂️
+// Optimized version of printer-manual.pdf saved as optimized-1556039930343.pdf 🎉
 ```
 
 ## API
@@ -67,6 +63,7 @@ $ pdfoptim --help
 
 ## Credits
 
+* [percentage-diff](https://github.com/rodrigobdz/percentage-diff) - Calculate percentage difference between two numbers
 * [generator-lnm](https://github.com/rodrigobdz/generator-lnm) - Awesome node module generator
 
 ## License