61 lines
1.5 KiB
JavaScript
61 lines
1.5 KiB
JavaScript
const callbacks = {}
|
|
|
|
/**
|
|
* 加载一个远程脚本
|
|
* @param {String} src 一个远程脚本
|
|
* @param {Function} callback 回调
|
|
*/
|
|
function loadScript(src, callback) {
|
|
const existingScript = document.getElementById(src)
|
|
const cb = callback || (() => {})
|
|
if (!existingScript) {
|
|
callbacks[src] = []
|
|
const $script = document.createElement('script')
|
|
$script.src = src
|
|
$script.id = src
|
|
$script.async = 1
|
|
document.body.appendChild($script)
|
|
const onEnd = 'onload' in $script ? stdOnEnd.bind($script) : ieOnEnd.bind($script)
|
|
onEnd($script)
|
|
}
|
|
|
|
callbacks[src].push(cb)
|
|
|
|
function stdOnEnd(script) {
|
|
script.onload = () => {
|
|
this.onerror = this.onload = null
|
|
callbacks[src].forEach(item => {
|
|
item(null, script)
|
|
})
|
|
delete callbacks[src]
|
|
}
|
|
script.onerror = () => {
|
|
this.onerror = this.onload = null
|
|
cb(new Error(`Failed to load ${src}`), script)
|
|
}
|
|
}
|
|
|
|
function ieOnEnd(script) {
|
|
script.onreadystatechange = () => {
|
|
if (this.readyState !== 'complete' && this.readyState !== 'loaded') return
|
|
this.onreadystatechange = null
|
|
callbacks[src].forEach(item => {
|
|
item(null, script)
|
|
})
|
|
delete callbacks[src]
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 顺序加载一组远程脚本
|
|
* @param {Array} list 一组远程脚本
|
|
* @param {Function} cb 回调
|
|
*/
|
|
export function loadScriptQueue(list, cb) {
|
|
const first = list.shift()
|
|
list.length ? loadScript(first, () => loadScriptQueue(list, cb)) : loadScript(first, cb)
|
|
}
|
|
|
|
export default loadScript
|