Faz a importação de um CSV para o banco de dados

csv-import.js

const { Writable } = require('stream');
const { createReadStream } = require('fs');
const Split = require('stream-split');

const input = createReadStream('./votacao_candidato_munzona_2018_PR.csv', { encoding: 'latin1' });

// const [nl] = Buffer.from('\n');
// const buffer = Buffer.from('Edvaldo\nSzymonek');
// console.log(buffer[7] === nl);


class DatabaseWriter extends Writable {

    constructor() {
        super();

        this.size = 100000;
        this.lines = [];
    }

    insert(records) {
        console.log('Inserting', records.length, 'records...');
        return Promise.resolve();
    }

    _write(buffer, encoding, done) {
        const line = buffer.toString();
        const values = line.split(';');

        this.lines.push(values);

        if (this.lines.length < this.size) {
            done();

        } else {
            this.insert(this.lines, done)
                .then(_ => {
                    this.lines = [];
                    done();
                });
        }
    }

    end() {
        this.insert(this.lines)
            .then(_ => console.log('Finished!'));
    }
}

input.pipe(new Split('\n'))
    .pipe(new DatabaseWriter());