promisify and lipstickify (#5)

.editorconfig

@@ -10,6 +10,3 @@ insert_final_newline = true
 [{package.json,*.yml}]
 indent_style = space
 indent_size = 2
-
-[*.md]
-trim_trailing_whitespace = false

.travis.yml

@@ -1,6 +1,5 @@
 sudo: false
 language: node_js
 node_js:
-  - 'stable'
-  - '0.12'
-  - '0.10'
+  - '6'
+  - '4'

cli.js

@@ -1,37 +1,41 @@
 #!/usr/bin/env node
 'use strict';
-var path = require('path');
-var meow = require('meow');
-var logSymbols = require('log-symbols');
-var arrify = require('arrify');
-var isProgressive = require('./');
-
-var cli = meow([
-	'Usage',
-	'  $ is-progressive <file> ...',
-	'  $ is-progressive < <file>',
-	'',
-	'Example',
-	'  $ is-progressive baseline.jpg progressive.jpg',
-	'  ✖ baseline.jpg',
-	'  ✔ progressive.jpg'
-]);
-
-function init(input) {
-	var exitCode = 0;
-
-	arrify(input).forEach(function (x) {
-		var p = isProgressive.fileSync(x);
+const path = require('path');
+const meow = require('meow');
+const logSymbols = require('log-symbols');
+const arrify = require('arrify');
+const isProgressive = require('./');
+
+const cli = meow(`
+	Usage
+	  $ is-progressive <file> ...
+	  $ is-progressive < <file>
+
+	Example
+	  $ is-progressive baseline.jpg progressive.jpg
+	  ✖ baseline.jpg
+	  ✔ progressive.jpg
+`);
+
+const log = (p, x) => {
+	console.log(p ? logSymbols.success : logSymbols.error, path.relative(process.cwd(), x));
+};
+
+const init = input => {
+	let exitCode = 0;
+
+	arrify(input).forEach(x => {
+		const p = isProgressive.fileSync(x);
 
 		if (!p) {
 			exitCode = 1;
 		}
 
-		console.log(p ? logSymbols.success : logSymbols.error, path.relative(process.cwd(), x));
+		log(p, x);
 	});
 
 	process.exit(exitCode);
-}
+};
 
 if (process.stdin.isTTY) {
 	if (cli.input.length === 0) {
@@ -41,5 +45,7 @@ if (process.stdin.isTTY) {
 
 	init(cli.input);
 } else {
-	process.stdin.pipe(isProgressive.stream(init));
+	isProgressive.stream(process.stdin).then(p => {
+		log(p, 'stdin');
+	});
 }

index.js

@@ -1,97 +1,74 @@
 'use strict';
-var fs = require('fs');
-var readChunk = require('read-chunk');
-var through = require('through2');
+const fs = require('fs');
+const readChunk = require('read-chunk');
 
 // http://en.wikipedia.org/wiki/JPEG
 // SOF2 [0xFF, 0xC2] = Start Of Frame (Progressive DCT)
-var SOF2 = 0xc2;
+const SOF2 = 0xc2;
 
-function search(buf) {
-	var currByte;
-	var prevByte;
-
-	for (var i = 0; i < buf.length; i++) {
-		currByte = buf[i];
-		prevByte = buf[i - 1];
+const search = buf => {
+	let prevByte;
 
+	for (const currByte of buf) {
 		if (prevByte !== 0xff) {
+			prevByte = currByte;
 			continue;
 		}
 
 		if (currByte === SOF2) {
 			return true;
 		}
+
+		prevByte = currByte;
 	}
 
 	return false;
-}
-
-exports.buffer = function (buf) {
-	return search(buf);
 };
 
-exports.stream = function (cb) {
-	var prevLastByte = new Buffer(1);
-	var searchDone = false;
+exports.buffer = search;
 
-	return through(function (data, enc, cb2) {
-		if (searchDone) {
-			cb(null, data);
-			return;
-		}
-
-		prevLastByte = new Buffer(data[data.length - 1]);
+exports.stream = stream => new Promise((resolve, reject) => {
+	let prevLastByte = new Buffer(1);
 
-		var res = exports.buffer(Buffer.concat([prevLastByte, data]), true);
+	const end = () => {
+		resolve(false);
+	};
 
-		if (res === true) {
-			searchDone = true;
-			cb(true);
-		}
+	stream.on('data', data => {
+		prevLastByte = new Buffer(data[data.length - 1]);
 
-		cb2(null, data);
-	}, function (cb2) {
-		if (!searchDone) {
-			cb(false);
+		if (search(Buffer.concat([prevLastByte, data]))) {
+			resolve(true);
+			stream.removeListener('end', end);
 		}
-
-		cb2();
 	});
-};
 
-exports.file = function (filepath, cb) {
-	// the metadata section has a maximum size of 65535 bytes
-	readChunk(filepath, 0, 65535, function (err, buf) {
-		if (err) {
-			cb(err);
-			return;
-		}
+	stream.on('error', reject);
 
-		cb(null, exports.buffer(buf));
-	});
-};
+	stream.on('end', end);
+});
+
+// the metadata section has a maximum size of 65535 bytes
+exports.file = filepath => readChunk(filepath, 0, 65535).then(search);
 
-exports.fileSync = function (filepath) {
+exports.fileSync = filepath => {
 	// we read one byte at the time here as it usually appears
 	// early in the file and reading 65535 would be wasteful
-	var currByte;
-	var prevByte;
-	var BUF_LENGTH = 1;
-	var buf = new Buffer(BUF_LENGTH);
-	var bytesRead = BUF_LENGTH;
-	var read = fs.openSync(filepath, 'r');
-	var isProgressive = false;
+	const BUF_LENGTH = 1;
+	const buf = new Buffer(BUF_LENGTH);
+	const read = fs.openSync(filepath, 'r');
+	let bytesRead = BUF_LENGTH;
+	let currByte;
+	let prevByte;
+	let isProgressive = false;
 
 	while (bytesRead === BUF_LENGTH) {
 		bytesRead = fs.readSync(read, buf, 0, 1);
 		currByte = buf[0];
 
-		if (prevByte === 0xff) {
-			if (currByte === SOF2) {
-				isProgressive = true;
-				break;
-			}
+		if (prevByte === 0xff && currByte === SOF2) {
+			isProgressive = true;
+			break;
 		}
 
 		prevByte = currByte;

package.json

@@ -11,7 +11,7 @@
   },
   "bin": "cli.js",
   "engines": {
-    "node": ">=0.10.0"
+    "node": ">=4"
   },
   "scripts": {
     "test": "xo && ava"
@@ -44,11 +44,13 @@
     "arrify": "^1.0.0",
     "log-symbols": "^1.0.1",
     "meow": "^3.6.0",
-    "read-chunk": "^1.0.0",
-    "through2": "^2.0.0"
+    "read-chunk": "^2.0.0"
   },
   "devDependencies": {
     "ava": "*",
     "xo": "*"
+  },
+  "xo": {
+    "esnext": true
   }
 }