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42 lines
1.1 KiB
42 lines
1.1 KiB
2 years ago
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'use strict'
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const MinipassPipeline = require('minipass-pipeline')
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class CachingMinipassPipeline extends MinipassPipeline {
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#events = []
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#data = new Map()
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constructor (opts, ...streams) {
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// CRITICAL: do NOT pass the streams to the call to super(), this will start
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// the flow of data and potentially cause the events we need to catch to emit
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// before we've finished our own setup. instead we call super() with no args,
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// finish our setup, and then push the streams into ourselves to start the
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// data flow
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super()
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this.#events = opts.events
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/* istanbul ignore next - coverage disabled because this is pointless to test here */
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if (streams.length) {
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this.push(...streams)
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}
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}
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on (event, handler) {
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if (this.#events.includes(event) && this.#data.has(event)) {
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return handler(...this.#data.get(event))
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}
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return super.on(event, handler)
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}
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emit (event, ...data) {
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if (this.#events.includes(event)) {
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this.#data.set(event, data)
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}
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return super.emit(event, ...data)
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}
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}
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module.exports = CachingMinipassPipeline
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