60 lines
1.5 KiB
JavaScript
60 lines
1.5 KiB
JavaScript
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'use strict';
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const { Transform } = require('stream');
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const JSON2CSVTransform = require('./JSON2CSVTransform');
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const { fastJoin } = require('./utils');
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class JSON2CSVAsyncParser {
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constructor(opts, transformOpts) {
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this.input = new Transform(transformOpts);
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this.input._read = () => {};
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this.transform = new JSON2CSVTransform(opts, transformOpts);
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this.processor = this.input.pipe(this.transform);
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}
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fromInput(input) {
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if (this._input) {
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throw new Error('Async parser already has an input.');
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}
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this._input = input;
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this.input = this._input.pipe(this.processor);
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return this;
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}
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throughTransform(transform) {
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if (this._output) {
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throw new Error('Can\'t add transforms once an output has been added.');
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}
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this.processor = this.processor.pipe(transform);
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return this;
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}
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toOutput(output) {
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if (this._output) {
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throw new Error('Async parser already has an output.');
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}
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this._output = output;
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this.processor = this.processor.pipe(output);
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return this;
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}
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promise(returnCSV = true) {
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return new Promise((resolve, reject) => {
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if (!returnCSV) {
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this.processor
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.on('finish', () => resolve())
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.on('error', err => reject(err));
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return;
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}
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let csvBuffer = [];
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this.processor
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.on('data', chunk => csvBuffer.push(chunk.toString()))
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.on('finish', () => resolve(fastJoin(csvBuffer, '')))
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.on('error', err => reject(err));
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});
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}
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}
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module.exports = JSON2CSVAsyncParser
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