47 lines
1.2 KiB
Plaintext
47 lines
1.2 KiB
Plaintext
'use strict';
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const {Transform} = require('stream');
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const alwaysFalse = () => false;
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class SkipWhile 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._condition = alwaysFalse;
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if (options) {
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'condition' in options && (this._condition = options.condition);
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}
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}
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_transform(chunk, encoding, callback) {
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const result = this._condition.call(this, chunk);
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if (result && typeof result.then == 'function') {
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result.then(
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flag => {
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if (!flag) {
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this._transform = this._passThrough;
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this.push(chunk);
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}
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callback(null);
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},
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error => callback(error)
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);
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} else {
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if (!result) {
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this._transform = this._passThrough;
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this.push(chunk);
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}
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callback(null);
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}
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}
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_passThrough(chunk, encoding, callback) {
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this.push(chunk);
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callback(null);
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}
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static make(condition) {
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return new SkipWhile(typeof condition == 'object' ? condition : {condition});
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}
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}
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SkipWhile.make.Constructor = SkipWhile;
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module.exports = SkipWhile.make;
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