@naturalcycles/nodejs-lib/dist/csv/csvWriter.js

Standard library for Node.js

// Inspired by: https://github.com/ryu1kn/csv-writer/
import { _assert } from '@naturalcycles/js-lib/error/assert.js';
export class CSVWriter {
    constructor(cfg) {
        this.cfg = {
            delimiter: ',',
            includeHeader: true,
            ...cfg,
        };
    }
    cfg;
    writeRows(rows) {
        let s = '';
        // Detect columns based on content, if not defined upfront
        this.cfg.columns ||= arrayToCSVColumns(rows);
        if (this.cfg.includeHeader && rows.length) {
            s += this.writeHeader() + '\n';
        }
        return s + rows.map(row => this.writeRow(row)).join('\n');
    }
    writeHeader() {
        _assert(this.cfg.columns, 'CSVWriter cannot writeHeader, because columns were not provided');
        return this.cfg.columns.map(col => this.quoteIfNeeded(col)).join(this.cfg.delimiter);
    }
    writeRow(row) {
        _assert(this.cfg.columns, 'CSVWriter cannot writeRow, because columns were not provided');
        return this.cfg.columns
            .map(col => this.quoteIfNeeded(String(row[col] ?? '')))
            .join(this.cfg.delimiter);
    }
    quoteIfNeeded(s) {
        return this.shouldQuote(s) ? this.quote(s) : s;
    }
    quote(s) {
        return `"${s.replaceAll('"', '""')}"`;
    }
    shouldQuote(s) {
        return s.includes(this.cfg.delimiter) || s.includes('"') || s.includes('\n') || s.includes('\r');
    }
}
export function arrayToCSVString(arr, cfg = {}) {
    const writer = new CSVWriter(cfg);
    return writer.writeRows(arr);
}
/**
 * Iterates over the whole array and notes all possible columns.
 */
export function arrayToCSVColumns(arr) {
    const cols = new Set();
    for (const row of arr) {
        for (const col of Object.keys(row)) {
            cols.add(col);
        }
    }
    return [...cols];
}