esbuild-copy-static-files/README.md

An esbuild plugin to copy static files that changed from a source directory to a destination directory

# esbuild-copy-static-files

![CI](https://github.com/nickjj/esbuild-copy-static-files/workflows/CI/badge.svg?branch=main)

An [esbuild](https://esbuild.github.io/) plugin to efficiently copy static
files from a source directory to a destination directory.

✔️ Only copy files that changed *(it compares an MD5 hash of each file)*  
✔️  No 3rd party dependencies *(it only uses a few functions from the Node standard library)*

## Why?

I mainly created this because a certain live reloading tool I use didn't filter
out files that didn't change. This resulted in dozens of unnecessary file being
copied and log output in development every time I changed a single CSS or JS
file. It was wildly inefficient.

This plugin fixes the above because it'll only copy static files if they
changed on disk since they were last copied.

### How it works at a high level

For most web apps, when it comes to my front-end I like the idea of this type of directory structure:

```sh
# This is where your assets are located and is used as input for esbuild.
assets/
├── css/
│   └── app.css
├── js/
│   └── app.js
├── static/
│   ├── images/
│   │   └── logo.png
│   ├── favicon.ico
│   ├── robots.txt
├── esbuild.config.js
├── package.json
├── postcss.config.js
├── tailwind.config.js
└── yarn.lock

# This is the output of where esbuild will write its file(s) to.
public/
├── css/
│   └── app.css
├── js/
│   └── app.js
├── images/
│   └── logo.png
├── favicon.ico
├── robots.txt
```

In my opinion it's really nice having all of your assets in 1 spot which then
get output to another location.

esbuild manages the `js/` directory and TailwindCSS (or whatever you prefer)
manages the `css/` directory but that leaves us with a bunch of static files
that are composed of HTML, icons, images, fonts and more.

This esbuild plugin will copy your static files to your esbuild output
directory. No processing will be done on these static files. It's a quick `cp`
and only files that have changed are copied so it's really efficient.

You can name your `static/` and `public/` directories and configure their paths
however you want. We'll go over all of the configuration options in a bit.

## Installation

```sh
# Prefer Yarn?
yarn add --dev esbuild-copy-static-files

# Or NPM instead?
npm install --save-dev esbuild-copy-static-files
```

## Getting Started

If you had the same directory structure as above, here's the bare minimum
esbuild config to get going:

```js
const esbuild = require('esbuild')
const copyStaticFiles = require('esbuild-copy-static-files')

esbuild.build({
  entryPoints: ['./js/app.js'],
  outfile: '../public/js/app.js',
  bundle: true,
  minify: true,
  sourcemap: false,
  watch: false,
  plugins: [copyStaticFiles()],
})
```

## Configuration

This plugin uses Node's [`fs.cpSync`
function](https://nodejs.org/api/fs.html#fscpsyncsrc-dest-options) under the
hood. Any option that it has can be configured here.

Here's a list of what you can configure and the default values if you don't
override them:

```js
  plugins: [
    copyStaticFiles({
      src: './static',
      dest: '../public',
      dereference: true,
      errorOnExist: false,
      filter: EXPLAINED_IN_MORE_DETAIL_BELOW,
      preserveTimestamps: true,
      recursive: true,
    })
  ],
```

**In most cases you'll likely only change the `src` and `dest` to fit your
project's directory structure.**

Here's the docs of every configurable option from Node's documentation:

- `src` source path to copy.
- `dest` destination path to copy to.
- `dereference` dereference symlinks.
- `errorOnExist` when `force` is `false` and the destination exists, throw an error.
- `filter` function to filter copied files / directories. Return `true` to copy the item, `false` to ignore it.
- `force` overwrite existing file or directory. The copy operation will ignore errors if you set this to false and the destination exists. Use the `errorOnExist` option to change this behavior.
- `preserveTimestamps` when `true` timestamps from `src` will be preserved.
- `recursive` copy directories recursively.

### How does the filter function work?

By default it will filter out, AKA skip copying any files that haven't changed.
It does this by getting the MD5 hash of each `src` and `dest` file. If both
files have the same MD5 hash then it get skipped.

This is nice because if you had let's say 50 static files and only 1 of them
changed then only 1 file will get copied.

#### Using a custom filter function

If you can think of a more efficient way of detecting which file(s) should get
copied you can customize the filter function by providing your own function
that returns `true` or `false` based on whatever criteria you prefer.

Here's an example of a simple filter function that always returns `true`:

```js
  plugins: [
    copyStaticFiles({
      filter: function () { return true },
    })
  ],
```

## About the author

- Nick Janetakis | <https://nickjanetakis.com> | [@nickjanetakis](https://twitter.com/nickjanetakis)

I'm a self taught developer and have been freelancing for the last ~20 years.
You can read about everything I've learned along the way on my site at
[https://nickjanetakis.com](https://nickjanetakis.com/).

There's hundreds of [blog posts / videos](https://nickjanetakis.com/blog/) and
a couple of [video courses](https://nickjanetakis.com/courses/) on web
development and deployment topics. I also have a
[podcast](https://runninginproduction.com) where I talk with folks about
running web apps in production.