40 lines
1016 B
Plaintext
40 lines
1016 B
Plaintext
'use strict';
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const {Transform} = require('stream');
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class Take extends Transform {
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constructor(options) {
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super(Object.assign({}, options, {writableObjectMode: true, readableObjectMode: true}));
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this._n = this._skip = 0;
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if (options) {
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'n' in options && (this._n = options.n);
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'skip' in options && (this._skip = options.skip);
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}
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if (this._skip <= 0) {
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this._transform = this._n > 0 ? this._countValues : this._doNothing;
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}
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}
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_transform(chunk, encoding, callback) {
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if (--this._skip <= 0) {
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this._transform = this._n > 0 ? this._countValues : this._doNothing;
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}
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callback(null);
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}
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_countValues(chunk, encoding, callback) {
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if (--this._n <= 0) {
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this._transform = this._doNothing;
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}
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this.push(chunk);
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callback(null);
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}
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_doNothing(chunk, encoding, callback) {
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callback(null);
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}
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static make(n) {
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return new Take(typeof n == 'object' ? n : {n});
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}
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}
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Take.make.Constructor = Take;
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module.exports = Take.make;
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