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83 lines
1.8 KiB
83 lines
1.8 KiB
const { Transform } = require('readable-stream') |
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function inherits (fn, sup) { |
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fn.super_ = sup |
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fn.prototype = Object.create(sup.prototype, { |
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constructor: { value: fn, enumerable: false, writable: true, configurable: true } |
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}) |
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} |
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// create a new export function, used by both the main export and |
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// the .ctor export, contains common logic for dealing with arguments |
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function through2 (construct) { |
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return (options, transform, flush) => { |
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if (typeof options === 'function') { |
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flush = transform |
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transform = options |
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options = {} |
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} |
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if (typeof transform !== 'function') { |
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// noop |
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transform = (chunk, enc, cb) => cb(null, chunk) |
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} |
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if (typeof flush !== 'function') { |
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flush = null |
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} |
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return construct(options, transform, flush) |
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} |
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} |
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// main export, just make me a transform stream! |
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const make = through2((options, transform, flush) => { |
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const t2 = new Transform(options) |
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t2._transform = transform |
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if (flush) { |
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t2._flush = flush |
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} |
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return t2 |
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}) |
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// make me a reusable prototype that I can `new`, or implicitly `new` |
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// with a constructor call |
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const ctor = through2((options, transform, flush) => { |
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function Through2 (override) { |
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if (!(this instanceof Through2)) { |
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return new Through2(override) |
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} |
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this.options = Object.assign({}, options, override) |
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Transform.call(this, this.options) |
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this._transform = transform |
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if (flush) { |
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this._flush = flush |
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} |
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} |
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inherits(Through2, Transform) |
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return Through2 |
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}) |
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const obj = through2(function (options, transform, flush) { |
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const t2 = new Transform(Object.assign({ objectMode: true, highWaterMark: 16 }, options)) |
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t2._transform = transform |
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if (flush) { |
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t2._flush = flush |
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} |
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return t2 |
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}) |
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module.exports = make |
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module.exports.ctor = ctor |
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module.exports.obj = obj
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