60 lines
1.4 KiB
JavaScript
60 lines
1.4 KiB
JavaScript
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const eventRegistryMap = new WeakMap()
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function getRegistry(instance) {
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let events = eventRegistryMap.get(instance)
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if (!events) {
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eventRegistryMap.set(instance, (events = Object.create(null)))
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}
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return events
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}
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export function $on(instance, event, fn) {
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if (Array.isArray(event)) {
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event.forEach((e) => $on(instance, e, fn))
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} else {
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const events = getRegistry(instance)
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;(events[event] || (events[event] = [])).push(fn)
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}
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return instance
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}
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export function $once(instance, event, fn) {
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const wrapped = (...args) => {
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$off(instance, event, wrapped)
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fn.call(instance, ...args)
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}
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wrapped.fn = fn
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$on(instance, event, wrapped)
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return instance
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}
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export function $off(instance, event, fn) {
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const vm = instance
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// all
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if (!event) {
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eventRegistryMap.set(instance, Object.create(null))
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return vm
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}
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// array of events
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if (Array.isArray(event)) {
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event.forEach((e) => $off(instance, e, fn))
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return vm
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}
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// specific event
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const events = getRegistry(instance)
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const cbs = events[event]
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if (!cbs) {
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return vm
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}
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if (!fn) {
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events[event] = undefined
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return vm
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}
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events[event] = cbs.filter((cb) => !(cb === fn || cb.fn === fn))
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return vm
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}
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export function $emit(instance, event, ...args) {
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instance && instance.$emit && instance.$emit(event, ...args)
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const cbs = getRegistry(instance)[event]
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if (cbs) {
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cbs.map((cb) => cb.apply(instance, args))
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}
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return instance
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}
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