https://github.com/syall/jsmin.js

A Clever CLI JavaScript Minifier written with Node.js inspired by Douglas Crockford's implementation.
https://github.com/syall/jsmin.js

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A Clever CLI JavaScript Minifier written with Node.js inspired by Douglas Crockford's implementation.

• Host: GitHub
• URL: https://github.com/syall/jsmin.js
• Owner: syall
• Created: 2020-01-16T05:21:10.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2020-01-16T23:13:01.000Z (almost 5 years ago)
• Last Synced: 2024-08-08T16:14:34.898Z (3 months ago)
• Language: JavaScript
• Homepage: https://www.npmjs.com/package/jsmin.js
• Size: 12.7 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# jsmin.js

## Overview

`jsmin.js` is a JavaScript Minifier given the target file uses `"use strict";` style.

## Features

The minifier applies these transformations:

- Removal of Nonessentials

- Removal of Comments

- Preservation of Shebangs

- Preservation of Strings

## Usage

```shell

./ (.)?

```

## Motivation

In my exploration of language parsing, I found [Douglas Crockford's work](https://www.crockford.com) where there is a [JavaScript Minifier](https://www.crockford.com/jsmin.html) that he implemented in C.

However, some of the code was verbose for a simple utility, so I wanted to write some clever (**not clean**) code that would produce a similar result.

Through multiple tests, I had to battle the syntax of JavaScript as I stripped nonessential elements of existing programs to produce unreadable functionally equivalent code.

However, this is not an obfuscator, as I decided that I did not want to change the `Object` output, such as `console.log({ a })`, in which changing the name of the variables would change the output (however, that might be good for another project idea).

Side Note: As a personal challenge, there are no `{` or `}` characters in the source code!

```shell

# Running jsmin.js on jsmin.js

./jsmin.js jsmin.js

jsmin.js     size: 1898

jsmin.min.js size: 1117

```

Without any comments or blank lines, the [source code](https://github.com/syall/jsmin.js/blob/master/jsmin.simp.js) comes out to 34 LOC which is much less than [Crockford's jsmin.c](https://github.com/douglascrockford/JSMin/blob/master/jsmin.c) with 319 LOC (although it includes a large comment block and blank lines, but is still significantly smaller overall).

## Example

Using the same code snippet in [Crockford's blog post](https://www.crockford.com/jsmin.html), these are the results using `jsmin.js`:

```shell

./jsmin.js example/is.js

example/is.js     size: 990

example/is.min.js size: 435

```

### Original

```javascript

// (c) 2001 Douglas Crockford

// 2001 June 3

// is

// The 'is' object is used to identify the browser.  Every browser edition

// identifies itself, but there is no standard way of doing it, and some of

// the identification is deceptive. This is because the authors of web

// browsers are liars. For example, Microsoft's IE browsers claim to be

// Mozilla 4. Netscape 6 claims to be version 5. This code is seriously

// wrongheaded and obsolete.

var is = {

    ie: navigator.appName == 'Microsoft Internet Explorer',

    java: navigator.javaEnabled(),

    ns: navigator.appName == 'Netscape',

    ua: navigator.userAgent.toLowerCase(),

    version: parseFloat(navigator.appVersion.substr(21)) ||

        parseFloat(navigator.appVersion),

    win: navigator.platform == 'Win32'

};

is.mac = is.ua.indexOf('mac') >= 0;

if (is.ua.indexOf('opera') >= 0) {

    is.ie = is.ns = false;

    is.opera = true;

}

if (is.ua.indexOf('gecko') >= 0) {

    is.ie = is.ns = false;

    is.gecko = true;

}

```

### Minified

```javascript

var is={ie:navigator.appName=='Microsoft Internet Explorer',java:navigator.javaEnabled(),ns:navigator.appName=='Netscape',ua:navigator.userAgent.toLowerCase(),version:parseFloat(navigator.appVersion.substr(21))||parseFloat(navigator.appVersion),win:navigator.platform=='Win32'};is.mac=is.ua.indexOf('mac')>=0;if(is.ua.indexOf('opera')>=0){is.ie=is.ns=false;is.opera=true;}if(is.ua.indexOf('gecko')>=0){is.ie=is.ns=false;is.gecko=true;}

```