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