避免使用全局变量有助于减少程序中的错误，并使代码更易于理解。
我想在多个文件中使用Months变量，而不需要重新声明它。
这正是JavaScript modules使用export和import关键字解决的问题：
./constants.ts：

export const months = [
  { name: 'January' },
  { name: 'February' },
  { name: 'March' },
  { name: 'April' },
  { name: 'May' },
  { name: 'June' },
  { name: 'July' },
  { name: 'August' },
  { name: 'September' },
  { name: 'October' },
  { name: 'November' },
  { name: 'December' },
] as const;

./another_module.ts：

import { months } from './constants.js';

console.log(months.map(obj => obj.name)); // ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]

将此代码添加到运行文件中（我认为它名为main.ts）

window.Months = [
{ name: 'January' },
{ name: 'February' },
{ name: 'March' },
{ name: 'April' },
{ name: 'May' },
{ name: 'June' },
{ name: 'July' },
{ name: 'August' },
{ name: 'September' },
{ name: 'October' },
{ name: 'November' },
{ name: 'December' }
];

和global.d.ts

declare var Months: { name: string }[]