Stream XLSX in NodeJS

xls-streamer.js

const R = require('ramda')
const { getXlsxStream } = require('xlstream');

const buildFilter = (filter) => {
    let query = {};
    for (let keys in filter) {
        if (filter[keys].constructor === Array && filter[keys].length > 0) {
            query[keys] = filter[keys];
        }
    }
    return query;
}

const filterRow = (row, query) => {
    for (let key in query) {
        if (row[key] === undefined || !query[key].includes(row[key])) {
            return false;
        }
    }
    return true;
}

module.exports = (file, selectedColumns = [], sheetIndex = 0, filters = {}) => {
    let container = []
    const query = buildFilter(filters);
    return new Promise((done, reject) => {

        (async () => {
            const stream = await getXlsxStream({
                filePath: file,
                sheet: sheetIndex,
                withHeader: true,
                ignoreEmpty: true,
            });
            stream.on('data', function (row) {
                console.log(row)
                if (!filterRow(row.formatted.obj, query))
                    return;

                // If passed, push only selected columns
                if (selectedColumns.length != 0) {
                    container.push(R.pick(selectedColumns, row.formatted.obj))
                    return;
                }

                // Else push all columns
                container.push(row.formatted.obj)
            });
            stream.on('end', function () {
                done(container)
            });
            stream.on('error', function (error) {
                reject(error)
            });
        })();

    })
}