babel-plugin-transform-media-imports-kefe v0.0.1

babel-plugin-transform-media-imports

note: If you are reading this on npm, please note that this README is only updated per release. Sometimes deficiencies in the README are fixed in master but not yet published so make sure to check the github (and open an issue :D) page if something here is incorrect!

When building an application using server-side rendering, the need to calculate aspect ratio's from image or video files in order to prevent layout jank often arises. While looking for alternatives — as to not have to write this myself — I stumbled upon some other packages:

• babel-plugin-transform-assets-import-to-string
• babel-plugin-file-loader

These seem to primarily concern themselves with outputting a prefixed path based off of the import statement, however. This does not include getting the width, height, or aspectRatio of a given image / video. This plugin attempts to solve these issues by providing a simple way to get what you need without having to jump through many hoops / module bundlers.

Transforms the following:

import avatar from 'avatar.jpg';

Into:

var avatar = {
    pathname: '/avatar.jpg',
    src: '/avatar.jpg',
    width: 280,
    height: 280,
    aspectRatio: 1,
    heightToWidthRatio: 1,
    type: 'jpg'
};

Table of Contents

• babel-plugin-transform-media-imports
• Table of Contents
• Changelog
  • 09-08-2019 v1.3.0
  • 08-08-2019 v1.2.0
  • 05-08-2019 v1.1.1
• Binary dependencies
• Node support
• Installation
• Usage
  • Importing an image
  • Exporting an image
  • Importing specific properties
  • Exporting specific properties
• Configuration
  • baseDir
  • pathnamePrefix
  • outputRoot
  • imageExtensions
  • videoExtensions
  • hash
  • base64

Changelog

dates are listed in dd-mm-yyyy format

09-08-2019 v1.3.0

• Add mkdirp dependency, back to 2 deps :/
• Fix issues with creating directories recursively in older (< 10.0.0) node versions

08-08-2019 v1.2.0

• Add ability to output files with outputRoot.
• Remove md5-file dependency, it's only 1 dep now :boom:.
• Make .svg file content available through a content property.
• Rename md5 option to hash, md5 now gets aliassed to hash for backwards compat.
  • Add algo option to specify a valid node crypto hash algorithm.

05-08-2019 v1.1.1

• Added meta information

Binary dependencies

This plugin depends on ffprobe to be installed and executable on the system in order to get information about video formats such as mp4 and webm. ffprobe comes installed with ffmpeg. Without ffprobe installed, images can still be processed.

Node support

This plugin is tested in the following NodeJS versions:

• Node.js 12.0.0
• Node.js 11.0.0
• Node.js 10.0.0
• Node.js 9.0.0
• Node.js 8.0.0

Installation

Add this plugin to your package / application with:

npm:

npm install -S babel-plugin-transform-media-imports

yarn:

yarn add babel-plugin-transform-media-imports

Afterwards, add the plugin to your .babelrc plugins:

{
    "plugins": ["transform-media-imports"]
}

Usage

After following the installation steps above, you can now directly import images and videos into your JS files. This will result in an object with some useful properties:

• pathname the path of the file with baseDir removed and pathnamePrefix prepended.
• src the same as pathname unless base64 was specified and the file size was less than base64.maxSize.
• hash when hash is enabled, this property contains the generated hash, undefined otherwise.
• type type of the media file, e.g. 'jpg', 'svg', 'mp4'
• width width in pixels of the media file
• height height in pixels of the media file
• content if the file is an svg, the content property will contain the raw svg file contents.
• aspectRatio calculated aspect ratio using width / height rounded to 3 decimal places.
• heightToWidthRatio calculated ratio using height / width rounded to 3 decimal places. (useful for ::after padding aspect ratio hack)

Importing an image

To import an image including all its properties:

import image from 'path/to/image.jpg';

Which will be transformed into:

var image = {
    pathname: 'path/to/image.jpg',
    src: 'path/to/image.jpg',
    width: 1234,
    height: 1234,
    aspectRatio: 1,
    heightToWidthRatio: 1,
    type: 'jpg'
};

Exporting an image

To export an image including all its properties:

export {default as image} from 'path/to/image.jpg';

When using \@babel/plugin-proposal-export-default-from, a default export can be used instead:

export image from 'path/to/image.jpg';

Either will be transformed into:

const _image = {
    pathname: 'path/to/image.jpg',
    src: 'path/to/image.jpg',
    width: 1234,
    height: 1234,
    aspectRatio: 1,
    heightToWidthRatio: 1,
    type: 'jpg'
};
export { _image as image };

Importing specific properties

If you only need to import a specific property, members may be imported using named imports:

import {width, height, heightToWidthRatio} from 'path/to/image.jpg';

Which will be transformed into:

const width = 1234;
const height = 1234;
const heightToWidthRatio = 1;

Exporting specific properties

If you only need to export a specific property, members may be exported using named exports:

export {width, height, heightToWidthRatio} from 'path/to/image.jpg';

Which will be transformed into:

export const width = 1234;
export const height = 1234;
export const heightToWidthRatio = 1;

Configuration

This is the default configuration of the plugin, each option is detailed below:

[
    'transform-media-imports',
    {
        baseDir: process.cwd(),
        pathnamePrefix: '',
        outputRoot: null,
        imageExtensions: ['jpeg', 'apng', ...require('image-size').types],
        videoExtensions: ['mp4', 'webm', 'ogv'],
        hash: false,
        base64: false
    }
]

baseDir

default: process.cwd()

Everything before this path gets removed from the src and pathname attributes.

pathnamePrefix

default: ''

After removing the baseDir, the pathnamePrefix gets prepended to the src and pathname attributes.

outputRoot

default: null

When specified, writes output file(s) to outputRoot/{pathname} where pathname is the specified media file's pathname attribute.

imageExtensions

default: ['jpeg', 'apng', ...require('image-size').types]

Specify supported image extensions that will be transformed. By default, all extensions that image-size supports are added to the list in addition to prepending 'jpeg' and 'apng' to allow for regex matching of files using that extension as well.

videoExtensions

default: ['mp4', 'webm', 'ogv']

Specify supported video extensions that will be transformed.

hash

formerly named md5, the old name is still supported and will work the same way

default: null

When set to true, adds a hash to the src and pathname attributes:

import {pathname} from 'avatar.jpg';

Transforms into:

const pathname = 'avatar-3h2jk5gjkh35guighjg3hj5ghdjkahd34kj.jpg'

When set to an object, adds an md5 hash configured by it. The following properties are configurable:

{
    length: 10, // trims md5 length to first <N> characters
    delimiter: '.', // delimiter to join filename and md5: [filename][delimiter][md5].[ext]
    algo: 'md5' // a valid node 'crypto' createHash algorithm such as md5 or sha256, defaults to md5
}

After applying the above configuration the import looks like this:

const pathname = 'avatar.3h2jk5gjkh.jpg'

base64

default: null

When set to true, sets the src attribute to the base64 string including web mime type when the file is <= 8192 bytes:

import {src} from 'avatar.jpg';

Transforms into:

var src = 'data:image/jpg;base64,/9j/4AAQSkZJRgABAQEASABIAAD/4QCCRXhp...'

When set to an object, the maxSize of 8192 may be overridden:

{
    maxSize: 10000 // allow files up to 10kb to be transformed to base64
}