pinafore/routes/_utils/autosize.js

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// Modified from https://github.com/jackmoore/autosize/blob/113f1b3/src/autosize.js
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// The only change is to remove IE-specific hacks,
// remove parent overflow checks, make page resizes more performant,
// add deferredUpdate, and add perf marks.
import { mark, stop } from './marks'
import debounce from 'lodash-es/debounce'
import throttle from 'lodash-es/throttle'
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const map = new Map()
let createEvent = (name) => new Event(name, {bubbles: true})
function assign (ta) {
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if (!ta || !ta.nodeName || ta.nodeName !== 'TEXTAREA' || map.has(ta)) {
return
}
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let heightOffset = null
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let cachedHeight = null
function init () {
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const style = window.getComputedStyle(ta, null)
if (style.boxSizing === 'content-box') {
heightOffset = -(parseFloat(style.paddingTop) + parseFloat(style.paddingBottom))
} else {
heightOffset = parseFloat(style.borderTopWidth) + parseFloat(style.borderBottomWidth)
}
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update()
}
function resize () {
mark('autosize:resize()')
let res = _resize()
stop('autosize:resize()')
return res
}
function _resize () {
const originalHeight = ta.style.height
ta.style.height = ''
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let endHeight = ta.scrollHeight + heightOffset
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if (ta.scrollHeight === 0) {
// If the scrollHeight is 0, then the element probably has display:none or is detached from the DOM.
ta.style.height = originalHeight
return
}
ta.style.height = endHeight + 'px'
return endHeight
}
const deferredUpdate = throttle(() => requestAnimationFrame(update), 100)
function update () {
mark('autosize:update()')
_update()
stop('autosize:update()')
}
function _update () {
let newHeight = resize()
if (cachedHeight !== newHeight) {
cachedHeight = newHeight
const evt = createEvent('autosize:resized')
try {
ta.dispatchEvent(evt)
} catch (err) {
// Firefox will throw an error on dispatchEvent for a detached element
// https://bugzilla.mozilla.org/show_bug.cgi?id=889376
}
}
}
const pageResize = debounce(update, 1000)
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const destroy = () => {
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window.removeEventListener('resize', pageResize, false)
ta.removeEventListener('input', deferredUpdate, false)
ta.removeEventListener('autosize:destroy', destroy, false)
ta.removeEventListener('autosize:update', update, false)
map.delete(ta)
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}
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ta.addEventListener('autosize:destroy', destroy, false)
window.addEventListener('resize', pageResize, false)
ta.addEventListener('input', deferredUpdate, false)
ta.addEventListener('autosize:update', update, false)
map.set(ta, {
destroy,
update
})
init()
}
function destroy (ta) {
const methods = map.get(ta)
if (methods) {
methods.destroy()
}
}
function update (ta) {
const methods = map.get(ta)
if (methods) {
methods.update()
}
}
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let autosize = (el, options) => {
if (el) {
Array.prototype.forEach.call(el.length ? el : [el], x => assign(x, options))
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}
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return el
}
autosize.destroy = el => {
if (el) {
Array.prototype.forEach.call(el.length ? el : [el], destroy)
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}
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return el
}
autosize.update = el => {
if (el) {
Array.prototype.forEach.call(el.length ? el : [el], update)
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}
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return el
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}
export { autosize }