A utility function to get element references directly from a HTML string.
Creating nested DOM elements with JS can be tedious and verbose; you either have to create and assemble them manually, or set the .innerHTML of a container element and then query for its children so that you can add event listeners etc. With fromHTML() you can do both in one go:
const {
modal,
cancelBtn,
confirmBtn
} = fromHTML(`
<div ref="modal" class="modal__overlay">
<div class="modal__container">
<div class="modal__content">Some message</div>
<button
ref="cancelBtn"
class="modal__cancel-btn"
>Cancel</button>
<button
ref="confirmBtn"
class="modal__confirm-btn"
>Confirm</button>
</div>
</div>
`)
cancelBtn.addEventListener('click', /* ... */)
confirmBtn.addEventListener('click', /* ... */)
document.body.appendChild(modal)Or actually add event listeners directly:
const { modal } = fromHTML(`
<div ref="modal" class="modal__overlay">
<div class="modal__container">
<div class="modal__content">This site uses cookies.</div>
<button
on="click:accept"
class="modal__confirm-btn"
>Accept</button>
<button
on="click:reject"
class="modal__cancel-btn"
>Reject</button>
</div>
</div>
`, {
accept () {
document.cookie = 'cookies_accepted=1'
modal.style.display = 'none'
},
reject () {
throw 'We gotta get out of this place!'
}
})Install as usual:
yarn add from-html
And in your JS:
import fromHTML from 'from-html'The script can also be downloaded or directly included from unpkg.com:
<script src="https://unpkg.com/from-html"></script>fromHTML(htmlString [, controller [, options]])
The values of the ref attributes will get mapped to the property names of the returned object; you can also get an array of elements (not a node list!) by appending square brackets to the ref name:
const names = ['Jane', 'John', 'Jimmy']
const { list, items } = fromHTML(`
<ul ref="list">
${names.map(name => `<li ref="items[]">${name}</li>`).join('')}
</ul>
`)Instead of a HTML string it's also possible to pass an ID selector of a template to use:
<script type="text/template" id="my-template">
<ul ref="list">
<li ref="items[]">Jane</li>
<li ref="items[]">John</li>
<li ref="items[]">Jimmy</li>
</ul>
</script>const { list, items } = fromHTML('#my-template')While at it, you can also add event listeners by providing a controller object and binding its methods with on attributes:
const { button } = fromHTML(`
<button ref="button" on="click:sayHello">Click me!</button>
`, {
sayHello () {
window.alert('Hello HTML!')
}
})The part before the colon specifies the type of the event, the part after it the method of the controller to call. Multiple events can be bound with a space-separated list:
const { button } = fromHTML(`
<button
ref="button"
on="mousedown:sayHello mouseup:sayGoodbye"
>Click me!</button>
`, {
sayHello () {
window.alert('Hello HTML!')
},
sayGoodbye () {
throw 'Goodbye!'
}
})If the method name is omitted, the controller object itself will be used to handle events (assuming of course it implements the EventListener interface):
const { button } = fromHTML(`
<button ref="button" on="mousedown mouseup">Click me!</button>
`, {
handleEvent ({ type }) {
switch (type) {
case 'mousedown':
window.alert('Hello HTML!')
break
case 'mouseup':
throw 'Goodbye!'
}
}
})The following options can be specified:
| Name | Type | Default | Description |
|---|---|---|---|
refAttribute |
string |
ref |
The attribute to get the element references from |
eventAttribute |
string |
on |
The attribute denoting event bindings |
removeRefAttribute |
boolean |
true |
Whether to remove the reference attribute afterwards |
removeEventAttribute |
boolean |
true |
Whether to remove the event attribute afterwards |
assignToController |
boolean|string |
false |
Whether to assign the element references to the controller, or to a given property of the controller if a string is provided |
For example, if you want to keep the ref attribute you might use data-* attributes for HTML compliance:
const { button } = fromHTML(`
<button data-ref="button">Click me!</button>
`, null, {
refAttribute: 'data-ref',
removeRefAttribute: false
})Instead of an options object you can also pass a boolean as a shorthand for assignToController:
class DisposableButton {
constructor (text) {
fromHTML(`
<button ref="_el" on="click">${text}</button>
`, this, true)
}
mount (target) {
target.append(this._el)
}
handleEvent ({ type }) {
if (type === 'click') {
this._el.remove()
}
}
}It is also possible to pass a string to specify a property to which the references should get assigned:
class SwitchButton {
constructor () {
fromHTML(`
<span ref="container">
<button ref="onBtn" on="click">on</button>
<button ref="offBtn" on="click" hidden>off</button>
</span>
`, this, 'refs')
}
mount (target) {
target.append(this.refs.container)
}
handleEvent ({ type }) {
const toggleHidden = el => {
el.hidden = !el.hidden
}
if (type === 'click') {
toggleHidden(this.refs.onBtn)
toggleHidden(this.refs.offBtn)
}
}
}In both cases the object to which the references got assigned will be returned (i.e. the controller itself or its specified property).
MIT @ m3g4p0p 2018
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