Hyper fast diffing algorithm for real DOM nodes ⚡
var morph = require('nanomorph')
var html = require('nanohtml')
var tree = html`<div>hello people</div>`
document.body.appendChild(tree)
// document.body === <body><div>hello people</div></body>
morph(tree, html`<div>nanananana-na-no</div>`)
// document.body === <body><div>nanananana-na-no</div></body>
morph(tree, html`<div>teeny, tiny, tin bottle</div>`)
// document.body === <body><div>teeny, tiny, tin bottle</div></body>To remove values from inputs, there's a few options:
html`<input class="beep" value=${null}>` // set the value to null
html`<input class="beep">` // omit property all togetherIt's common to work with lists of elements on the DOM. Adding, removing or
reordering elements in a list can be rather expensive. To optimize this you can
add an id attribute to a DOM node. When reordering nodes it will compare
nodes with the same ID against each other, resulting in far fewer re-renders.
This is especially potent when coupled with DOM node caching.
var el = html`
<section>
<div id="first">hello</div>
<div id="second">world</div>
</section>
`Sometimes we want to tell the algorithm to not evaluate certain nodes (and its
children). This can be because we're sure they haven't changed, or perhaps
because another piece of code is managing that part of the DOM tree. To achieve
this nanomorph evaluates the .isSameNode() method on nodes to determine if
they should be updated or not.
var el = html`<div>node</div>`
// tell nanomorph to not compare the DOM tree if they're both divs
el.isSameNode = function (target) {
return (target && target.nodeName && target.nodeName === 'DIV')
}There are situations where two elements should never be morphed, but replaced.
nanomorph automatically does this for elements with different tag names. But if
we're implementing a custom component system, for example, components of
different types should probably be treated as if they had different tags—even
if they both render a <div> at their top level.
Nodes can have an optional data-nanomorph-component-id attribute. nanomorph
will only ever morph nodes if they both have the same value in this attribute.
If the values differ, the old node is replaced with the new one.
var el = html`<div data-nanomorph-component-id="a">hello</div>`
var el2 = html`<div data-nanomorph-component-id="b">goodbye</div>`
assert.equal(nanomorph(el, el2), el2)nanomorph doesn't have an opinion on the values of the data-nanomorph-component-id
attribute, so we can decide the meaning we give it on a case by case basis. There
could be a unique ID for every type of component, or a unique ID for every
instance of a component, or any other meaning.
It's quite similar actually; the API of this library is completely compatible
with morphdom and we've borrowed a fair few bits. The main difference is that
we copy event handlers like onclick, don't support browsers that are over a
decade old, and don't provide custom behavior by removing all hooks. This way
we can guarantee a consistent, out-of-the box experience for all your diffing
needs.
Node has no concept of a DOM - server side rendering is basically fancy string concatenation. If you want to combine HTML strings in Node, check out hyperstream.
Nanomorph was optimized for simplicity, but different situations might require different tradeoffs. So in order to allow folks to build their own implementation we expose our test suite as a function you can call. So regardless if you're doing it to solve a problem, or just for fun: you can use the same tests we use for your own implementation. Yay! ✨
Diff a tree of HTML elements against another tree of HTML elements and create a patched result that can be applied on the DOM.
$ npm install nanomorph