build.js

// To do: next major: generate one file.

import assert from 'node:assert/strict'
import fs from 'node:fs/promises'
import {dsvFormat} from 'd3-dsv'
import {fetch} from 'undici'

const response = await fetch(
  'https://www.loc.gov/standards/iso639-2/ISO-639-2_utf-8.txt'
)
let text = await response.text()

/** @type {Record<string, string>} */
const bTo1 = {}
/** @type {Record<string, string>} */
const tTo1 = {}
/** @type {Record<string, string>} */
const bTo2T = {}
/** @type {Record<string, string>} */
const tTo2B = {}
let index = -1

// BOM.
if (text.codePointAt(0) === 0xfeff) {
  text = text.slice(1)
}

const data = dsvFormat('|')
  .parse('b|t|i|n\n' + text)
  .map(function (d) {
    assert(d.n, 'expected name in all languages')
    assert(d.b, 'expected bibliographic in all languages')
    return {
      name: d.n,
      iso6392B: d.b,
      iso6392T: d.t || undefined,
      iso6391: d.i || undefined
    }
  })

while (++index < data.length) {
  const d = data[index]

  if (d.iso6391) {
    bTo1[d.iso6392B] = d.iso6391
    if (d.iso6392T) tTo1[d.iso6392T] = d.iso6391
  }

  if (d.iso6392T) {
    bTo2T[d.iso6392B] = d.iso6392T
    tTo2B[d.iso6392T] = d.iso6392B
  }
}

await fs.writeFile(
  '2.js',
  [
    '/**',
    ' * @typedef Language',
    ' *   One language.',
    ' * @property {string} name',
    ' *   Language name.',
    ' * @property {string} iso6392B',
    ' *   Bibliographic ISO 639-2 code.',
    ' * @property {string | undefined} [iso6392T]',
    ' *   Terminologic ISO 639-2 code (if different than `iso6392B`).',
    ' * @property {string | undefined} [iso6391]',
    ' *   ISO 639-1 code (if available).',
    ' */',
    '',
    '/**',
    ' * List of languages.',
    ' *',
    ' * @type {Array<Language>}',
    ' */',
    'export const iso6392 = ' + JSON.stringify(data, undefined, 2),
    ''
  ].join('\n')
)

await fs.writeFile(
  '2b-to-1.js',
  [
    '/**',
    ' * Map of ISO 639-2 bibliographic codes (`dut`) to ISO 639-1 codes (`nl`).',
    ' *',
    ' * @type {Record<string, string>}',
    ' */',
    'export const iso6392BTo1 = ' + JSON.stringify(bTo1, undefined, 2),
    ''
  ].join('\n')
)

await fs.writeFile(
  '2t-to-1.js',
  [
    '/**',
    ' * Map of ISO 639-2 terminologic codes (`nld`) to ISO 639-1 codes (`nl`).',
    ' *',
    ' * @type {Record<string, string>}',
    ' */',
    'export const iso6392TTo1 = ' + JSON.stringify(tTo1, undefined, 2),
    ''
  ].join('\n')
)

await fs.writeFile(
  '2t-to-2b.js',
  [
    '/**',
    ' * Map of ISO 639-2 terminologic codes (`nld`) to bibliographic codes (`dut`).',
    ' *',
    ' * @type {Record<string, string>}',
    ' */',
    'export const iso6392TTo2B = ' + JSON.stringify(tTo2B, undefined, 2),
    ''
  ].join('\n')
)

await fs.writeFile(
  '2b-to-2t.js',
  [
    '/**',
    ' * Map of ISO 639-2 bibliographic codes (`dut`) to terminologic codes (`nld`).',
    ' *',
    ' * @type {Record<string, string>}',
    ' */',
    'export const iso6392BTo2T = ' + JSON.stringify(bTo2T, undefined, 2),
    ''
  ].join('\n')
)