generateBatch

Batch.js

const fs = require('fs')
function MDTR(initialProps) {
    this.props = initialProps;
    this.defaultValues = {
        jobId: 'xpto',
        bucketStart: 'bucketTest',
        nomeDoArquivoTxt: 'example.txt'
    };
    
    this.getLinesizeInBytes = function(filename) {
        const buf = new Buffer(500 - 0);
        const fd = fs.openSync(filename, 'r');
        //resolver isso ainda!
        fs.readSync(fd, buf, 0, 500 - 0, 0);
        fs.closeSync(fd);
        const lines = buf.toString().split('\n')
        if (lines.length) return lines[0].length + 1;
    };
    
    this.getFilesizeInBytes = function(filename) {
        const stats = fs.statSync(filename)
        const fileSizeInBytes = stats.size
        
        return fileSizeInBytes + 1
    }
    
    this.getFilePart = function(filename, start, end) {
        if (start < 0 || end < 0 || end < start || end - start > 0x3fffffff)
            throw new Error('bad start, end');
        if (end - start === 0)
            return new Buffer(0);
    
        const buf = new Buffer(end - start);
        const fd = fs.openSync(filename, 'r');
        fs.readSync(fd, buf, 0, end - start, start);
        fs.closeSync(fd);
        lines = buf.toString().split('\n')
        
        return buf;
    }
    
    this.generateBatches = function () {
        do {
            randomJson = {
                ...this.defaultValues,
                range: {
                    start: this.readerConfig.range.start,  
                    end: this.readerConfig.range.end
                }
            }
            this.readerConfig.queueParts.push(randomJson);
            this.readerConfig.range.start = this.readerConfig.range.end;
            this.readerConfig.range.end += this.readerConfig.lineBreak;
        }
        while (this.readerConfig.range.end <= this.readerConfig.size);
        
        return this.readerConfig.queueParts;
    }
    this.readerConfig = {
        range: {
            start: 0,
            end: this.getLinesizeInBytes(this.defaultValues.nomeDoArquivoTxt)
        },
        lineBreak: this.getLinesizeInBytes(this.defaultValues.nomeDoArquivoTxt),
        queueParts: [],
        size: this.getFilesizeInBytes(this.defaultValues.nomeDoArquivoTxt)
    }
}

const mdtr = new MDTR();
console.log(mdtr.generateBatches());