require auto-complete doesn't suggest module name for module definitions without declare module syntax

1. When a type definition file is added without declare module "module-name" syntax, the auto-complete doesn't work if the module is imported via require.
2. Secondly what is the correct way of adding type-definitions files which refer other type-definitions files via /// reference call. (For example how to provide auto-completion for lodash library after require('lodash') call)

monaco-editor version: 0.20.0
Browser: Google Chrome Version 83.0.4103.116 (Official Build) (64-bit)
OS: macOS Catalina 10.15.3
Playground code that reproduces the issue:

// Add additonal d.ts files to the JavaScript language service and change.
// Also change the default compilation options.
// The sample below shows how a class Facts is declared and introduced
// to the system and how the compiler is told to use ES6 (target=2).

// validation settings
monaco.languages.typescript.javascriptDefaults.setDiagnosticsOptions({
	noSemanticValidation: true,
	noSyntaxValidation: false
});

// compiler options
monaco.languages.typescript.javascriptDefaults.setCompilerOptions({
	target: monaco.languages.typescript.ScriptTarget.ES6,
	allowNonTsExtensions: true,
        allowJs:true
});

// extra libraries
monaco.languages.typescript.javascriptDefaults.addExtraLib(
    `// Type definitions for atob 2.1
// Project: https://git.coolaj86.com/coolaj86/atob.js.git
// Definitions by: John Wright <https://github.com/johngeorgewright>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
// TypeScript Version: 2.1
export = _default;
declare function _default(str: string): string;
`
	, 'ts:filename/facts.d.ts');

var jsCode = "let x = require('atob');"

monaco.editor.create(document.getElementById("container"), {
	value: jsCode,
	language: "javascript"
});

Start with the provided Monaco Playground snippet, especially javascriptDefaults.addExtraLib, setCompilerOptions, and the require('atob') example. Reproduce the missing completion and investigate how extra .d.ts libraries and /// reference directives are resolved. Done means the reported module-definition case has expected autocomplete behavior, with the reference-file usage clarified.