global.js

/* 

This script reads the nearby global.d.ts file and exports a list of imports as
an object. Imports need to follow the same structure as the example below. This
script only works with default exports but could be modified to use named
exports instead.

Example:

`global.d.ts`

    import _$ from 'jquery';
    import _Handlebars from 'handlebars';
    import whatever from './foobar.js';

    declare global {
      interface Window {
        $: typeof _$;
        Handlebars: typeof _Handlebars;
        foobar: typeof whatever;
      }
    }

`[any].js`

    const globals = require('./global.js');
    console.dir(globals);
    // {
    //   '$': 'jquery',
    //   Handlebars: 'handlebars',
    //   foobar: './foobar.js'
    // }

*/

const fs = require('fs');
const { parse } = require('@typescript-eslint/typescript-estree');

function getGlobals(input) {
  const ast = parse(input);
  const imports = {};
  const globals = {};

  for (let statement of ast.body) {
    if (statement.type === 'ImportDeclaration') {
      for (let specifier of statement.specifiers) {
        if (specifier.type === 'ImportDefaultSpecifier') {
          imports[specifier.local.name] = statement.source.value;
        }
      }
    } else if (statement.type === 'TSModuleDeclaration') {
      if ( statement.id.name !== 'global'
        || statement.body.type !== 'TSModuleBlock'
      ) continue;
      for (let globalVar of statement.body.body) {
        if ( globalVar.type !== 'TSInterfaceDeclaration'
          || globalVar.id.name !== 'Window'
        ) continue;
        for (let windowVar of globalVar.body.body) {
          if ( windowVar.type !== 'TSPropertySignature'
            || windowVar.typeAnnotation.type !== 'TSTypeAnnotation'
            || windowVar.typeAnnotation.typeAnnotation.type !== 'TSTypeQuery'
            || windowVar.typeAnnotation.typeAnnotation.exprName.type !== 'Identifier'
          ) continue;
          if (imports[windowVar.typeAnnotation.typeAnnotation.exprName.name]) {
            globals[windowVar.key.name] = imports[windowVar.typeAnnotation.typeAnnotation.exprName.name];
          }
        }
      }
    }
  }

  return globals;
}

/** @type {{ [name: string]: string }} */
module.exports = getGlobals(fs.readFileSync(__dirname + '/global.d.ts'));