@thi.ng/csv/format.js

Customizable, transducer-based CSV parser/object mapper and transformer

import { isArray } from "@thi.ng/checks/is-array";
import { isIterable } from "@thi.ng/checks/is-iterable";
import { wrap } from "@thi.ng/strings/wrap";
import { compR } from "@thi.ng/transducers/compr";
import { iterator } from "@thi.ng/transducers/iterator";
import { isReduced } from "@thi.ng/transducers/reduced";
import { str } from "@thi.ng/transducers/str";
import { transduce } from "@thi.ng/transducers/transduce";
function formatCSV(opts = {}, src) {
  return isIterable(src) ? iterator(formatCSV(opts), src) : (rfn) => {
    let { cols = [], delim = ",", quote = '"', header } = opts;
    let colTx;
    const reQuote = new RegExp(quote, "g");
    const reduce = rfn[2];
    let headerDone = false;
    return compR(rfn, (acc, row) => {
      if (!headerDone) {
        if (!header && !isArray(row)) {
          header = Object.keys(row);
        }
        colTx = isArray(cols) ? cols : header ? header.map(
          (id) => cols[id]
        ) : [];
      }
      const $row = isArray(row) ? row : header.map((k) => row[k]);
      const line = (header || $row).map((_, i) => {
        const val = $row[i];
        const cell = val != null ? colTx[i] ? colTx[i](val) : String(val) : "";
        return cell.indexOf(quote) !== -1 ? wrap(quote)(
          cell.replace(
            reQuote,
            `${quote}${quote}`
          )
        ) : cell;
      }).join(delim);
      if (!headerDone) {
        if (header) {
          acc = reduce(acc, header.join(delim));
        } else {
          header = $row;
        }
        headerDone = true;
        !isReduced(acc) && (acc = reduce(acc, line));
        return acc;
      } else {
        return reduce(acc, line);
      }
    });
  };
}
const formatCSVString = (opts = {}, src) => transduce(formatCSV(opts), str(opts.rowDelim || "\n"), src);
export {
  formatCSV,
  formatCSVString
};