Asset-parser NPM

asset-parser

Asset Parser parses SVG bundles and turns them in to usable SVG assets that can be used in React and React-Native. It also provider a way to transform the assets on the fly if needed.

This module is designed to be used with the asset-provder.

Installation

If you are using this on the web, with React:

npm install --save asset-parser

If you run this on react-native you also need to manually install the react-native-svg dependency.

API

The parser class is directly exported from the module:

import AssetParser from 'asset-parser';

const ap = new AssetParser();

And it exposes the following methods:

parse

Parses the actual data into an object structure that contains the various of assets that were bundled in the received payload. It requires the following arguments.

format Either bundle or single.
data The data that needs to be parsed.
fn Error first completion callback.

ap.parse('bundle', '{..}', (err, svgs) => {

});

The svgs argument is alway specified, even in case of an error, where it will be an empty object. When parsing has completed successfully the object will be a mapping of <name of the asset> and an <Asset> instance.

It's important to know that while parsing of the payload is complete, we will not parse and transform the actual contents of the SVG until it's actually rendered. So if there are SVG's in the bundle that you are not using, it will not cost you any CPU cycles.

See Asset.render for more detailed information on rendering the assets.

modify

Allows you to modify the SVG's on the fly, this allows you to re-color, resize, change and even completely replace parts of SVG assets. It requires the following arguments:

name The name of the property where the modifier should trigger on.
fn Callback function that will do the modifications. The function receives 3 arguments:
- Attributes that will be introduced to child component.
- Properties that are passed in from asset.render({ props here }) method.
- The child component.

ap.modify('color', (attr, props, child) => {

});

It's worth noting that you can assign multiple modifiers per property. They are called in a FIFO order.

The following examples will give an indication of the flexibility and power of the modification system:

child filtering

As the modifier is called for every element in the SVG asset, you can do some filtering based on received child. As this is a React.Element it will give you access to child.props, but more importantly it's type using child.type.

ap.modify('fill', function (attr, props, child) {
  if (child.type !== 'G') return;
  if (attr.fill) return;

  attr.fill = props.fill;
});

child replacement

If you want to replace a child completely, you can return a new React.Element.

import { Circle } from 'svgs';

ap.modify('circle', function (attr, props, child) {
  if (child.type !== 'Rect') return;

  return (
    <Circle radius={ 10 } />
  );
});

modifiers

Returns an array of properties that we have modifiers registered for.

ap.modify('foo', () => { });
ap.modify('foo', () => { });
ap.modify('bar', () => { });

console.log(ap.modifiers()) // [ "foo", "bar" ]

encode

Encodes a given payload in to string. It prefixes the resulting string with the supplied version number. It requires 3 arguments:

version Version number of the specification.
data Object/array that needs to be encoded.
fn Error first completion callback.

import { encode } from 'asset-parser';

const data = { foo: 'bar' };
const version = '1.33.7';

encode(version, data, (err, str) => {

});

The example above would generate the following string as output;

1.33.7§{"foo":"bar"}

decode

Decodes the payload. It requires 2 arguments:

data String that needs to be encoded.
fn Error first completion callback.

import { decode } from 'asset-parser';

const str = '1.33.7§{"foo":"bar"}';
decode(str, (err, payload) => {

});

The resulting payload argument will be an object that will contain the following keys:

version The extracted version number from data string. This is version of the specification that was used to encode the data.
data The decoded data.

version

Exposes the current version of the specification that we encode the payload in.

import { version } from 'asset-parser';

Asset

The asset is our internal class that represents a single SVG item/result. It provides some optimizations and hooks to alter SVG's on the fly. It is exposed as export and can be accessed using.

import { Asset } from 'asset-parser';

The constructor requires 2 arguments:

data The data structure that needs to be transformed.
hooks Hooks that are used to modify the SVG elements.

Asset.render

Returns the SVG elements for the given asset. It accepts a single argument:

props Addition props that need to be introduced on the SVG, the modify functions will also receive these as arguments.

as.parser('bundle', 'string of bundle', (err, svgs) => {
  const asset = svgs['name of the file'];

  const { props, svg } = asset.render();

  console.log(props, svg);
  console.log(asset.render({ fill: 'red' }));
});