Combining a stream with a entire dataset

The main module exported by the package leverages the Node.js stream transform API. However, the input doesn't have to be a readable stream. Instead, it could be a CSV string and a Buffer. Also, the output doesn't have to be a writable stream, it could be a user callback function.

Uses it for convenience in case you are already interacting with a readable stream or a writable stream. It is not scalable because it implies that you either have all CSV dataset in memory and wish to pipe the generated records into a stream writer or that you have a stream reader generating a CSV data stream and wish to obtain a full dataset with all the records.

The signature of the output stream example is const stream = parse(input, [options]). It takes an input string and an options object as arguments and return a readable stream.

import assert from "node:assert";
import dedent from "dedent";
import { parse } from "csv-parse";

const records = [];
parse(
  dedent`
    "1","2","3"
    "a","b","c"
  `,
  {
    trim: true,
    skip_empty_lines: true,
  },
)
  // Use the readable stream api
  .on("readable", function () {
    let record;
    while ((record = this.read()) !== null) {
      records.push(record);
    }
  })
  // When we are done, test that the parsed records matched what expected
  .on("end", function () {
    assert.deepStrictEqual(records, [
      ["1", "2", "3"],
      ["a", "b", "c"],
    ]);
  });

./packages/csv-parse/samples/mixed.output_stream.js

Inversely, the signature of the input stream example is const stream = parse([options], callback). It takes an options object and a callback function as arguments and return a writable stream.

import assert from "node:assert";
import { parse } from "csv-parse";

// Create the parser
const parser = parse(
  {
    delimiter: ":",
  },
  function (err, records) {
    assert.deepStrictEqual(records, [
      ["root", "x", "0", "0", "root", "/root", "/bin/bash"],
      ["someone", "x", "1022", "1022", "", "/home/someone", "/bin/bash"],
    ]);
  },
);
// Write data to the stream
parser.write("root:x:0:0:root:/root:/bin/bash\n");
parser.write("someone:x:1022:1022::/home/someone:/bin/bash\n");
// Close the readable stream
parser.end();

./packages/csv-parse/samples/mixed.output_stream.js