@danielnixon/vdom-parser

v1.3.2

Published

2 years ago

A client-side DOM to vdom parser based on DOMParser API, compatible with virtual-dom

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danielnixon

dom vdom parser virtual-dom

vdom-parser

A client-side DOM to vdom parser based on DOMParser API, compatible with virtual-dom.

Motivation

We use virtual-dom with progressive enhancement in mind: we use server-side rendering to achieve good first-page performance then re-attach vdom rendering client-side.

This means we need a solid implementation of html to vdom parser, while there are existing implementations, we would like a solution that's well-tested and make use of existing browser API.

Hence vdom-parser, a small module that bridges the gap between server-side and client-side rendering.

Features

Use DOMParser for better performance and smaller filesize (around 10KB when minified).
No direct dependency, peer-dependent on virtual-dom major version (v2 currently).
VNode key support to minimize re-rendering.
100% test coverage, covering common usage such as inline svg, style and script tags (unfortunately phantomjs still lacks HTML support in DOMParser, so our travis coverage remains incomplete).

Browser support

For DOM element input, all modern browsers are supported.
For HTML string input, your browser need to support HTML input on DOMParser API.
Using DOMParser polyfill you can make this works on older browsers and phantomjs, see test cases comment on potential gotcha, and always trim your string before input.
For IE9 and HTML string input, using polyfill we can get most nodes under document.body to work, but anything else will throw Invalid target element for this operation. Maybe better to cut the mustard and use server-side rendering.
For Opera 12, be aware that their DOM attributes are not namespaced, it doesn't affect virtual-dom diffing or patching, but don't expect properties['xlink:href'] to exists.
To minimize client-side patching, you can output server-rendered HTML minified (instead of formatted with newlines and indents), this removes unnecessary text node from your generated vdom so virtual-dom don't have to remove or mutate them.

Install

npm install vdom-parser --save

Usage

// server-side render
var parser = require('vdom-parser');
var nodeCache = document.body;
var vdomCache = parser(nodeCache);

// client-side render
var vdom = h('div', 'hello');

// diff and patch
var patches = diff(vdomCache, vdom);
patch(nodeCache, patches);

See test cases for more examples.

API

parser(node, attr)

Returns a VNode or VText, see virtual-dom documentation.

node

Should be a DOM Element or HTML String.

Note: for string input, <html>, <body>, <head> will return empty VText as we only support nodes under document.body or document.head. DOM element input doesn't have this limit.

attr

Optional attribute name (eg. 'id' or 'data-id') for VNode key lookup, exposing VNode key as html attribute to minimize client-side patching.

License

MIT

Acknowledgement

Thanks to marcelklehr/vdom-virtualize and TimBeyer/html-to-vdom for their work on this topic.