feat: Introduce command-line generator for custom time zone data

Author: prantlf

bin/create-timezone-data

@@ -0,0 +1,58 @@
+#!/usr/bin/env node
+
+'use strict'
+
+const commander = require('commander')
+const { createTimeZoneData } = require('../util/data-creator')
+const pkg = require('../package.json')
+
+commander.version(pkg.version)
+  .description('Generates time zone data for a selected year range.')
+  .usage('[options] <first year> <last year>')
+  .option('-a, --all-years', 'includes all available years')
+  .option('-c, --as-cjs-module', 'format the time zone data as a CommonJS module')
+  .option('-d, --as-amd-module', 'format the time zone data as an AMD module')
+  .option('-m, --as-module', 'format the time zone data as a JavaScript module')
+  .option('-n, --umd-name <name>', 'UMD global export name, if not "timeZoneData"')
+  .option('-o, --output-file <file>', 'write the time zone data to a file')
+  .option('-u, --as-umd-module', 'format the time zone data as an UMD module')
+  .option('-o, --output-file <file>', 'write the time zone data to a file')
+
+commander.on('--help', function () {
+  console.log()
+  console.log('  Time zone data are printed on the standard output as JSON by default.')
+  console.log()
+  console.log('  Examples:')
+  console.log()
+  console.log('    $ create-timezone-data 2012 2022')
+  console.log('    $ create-timezone-data -m -o custom-data.js 1970 2038')
+})
+
+commander.parse(process.argv)
+const [ firstYear, lastYear ] = commander.args
+if (!(firstYear && lastYear) && !commander.allYears) {
+  commander.help()
+}
+
+const {
+  asModule, asCjsModule, asAmdModule, asUmdModule, umdName, outputFile
+} = commander
+createTimeZoneData({
+  firstYear,
+  lastYear,
+  asModule,
+  asCjsModule,
+  asAmdModule,
+  asUmdModule,
+  umdName,
+  outputFile
+})
+  .then(timeZoneData => {
+    if (!outputFile) {
+      console.log(timeZoneData)
+    }
+  })
+  .catch(error => {
+    console.error(error.message)
+    process.exitCode = 1
+  })

util/data-creator.js

@@ -0,0 +1,65 @@
+const { outputFile: writeFile } = require('fs-extra')
+const tz = require('../node_modules/moment-timezone/moment-timezone-utils').tz
+const groupLeaders = require('./data/group-leaders.json')
+const unpackedTimeZoneData = require('./data/unpacked.json')
+const packedTimeZoneData = require('./data/packed.json')
+
+function limitData (firstYear, lastYear) {
+  return firstYear && lastYear
+    ? tz.filterLinkPack(unpackedTimeZoneData, firstYear, lastYear, groupLeaders)
+    : packedTimeZoneData
+}
+
+function formatES6Module (content) {
+  return `export default ${content}`
+}
+
+function formatCJSModule (content) {
+  return `module.exports = ${content}`
+}
+
+function formatAMDModule (content) {
+  return `define(function () {
+  return ${content}
+})`
+}
+
+function formatUMDModule (content, umdName) {
+  return `(function (global, factory) {
+  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+  typeof define === 'function' && define.amd ? define(['exports'], factory) :
+  factory(global.${umdName || 'timeZoneData'} = {})
+} (this, (function (exports) {
+  Object.assign(exports, ${content})
+  Object.defineProperty(exports, '__esModule', { value: true })
+})))`
+}
+
+function createTimeZoneData (options = {}) {
+  const {
+    asModule, asCjsModule, asAmdModule, asUmdModule, umdName,
+    firstYear, lastYear, outputFile
+  } = options
+  const data = limitData(firstYear, lastYear)
+  let content = JSON.stringify(data, undefined, 2)
+  if (asModule) {
+    content = formatES6Module(content)
+  } else if (asCjsModule) {
+    content = formatCJSModule(content)
+  } else if (asAmdModule) {
+    content = formatAMDModule(content)
+  } else if (asUmdModule) {
+    content = formatUMDModule(content, umdName)
+  }
+  if (outputFile) {
+    if (firstYear && lastYear) {
+      console.log(`Writing time zone data for ${firstYear}-${lastYear} to "${outputFile}"...`)
+    } else {
+      console.log(`Writing all time zone data to "${outputFile}"...`)
+    }
+    return writeFile(outputFile, content)
+  }
+  return Promise.resolve(content)
+}
+
+exports.createTimeZoneData = createTimeZoneData