closure.js

import { getName, quotePath } from '../utils/map-helpers.js';
import getInteropBlock from './shared/getInteropBlock.js';
import getExportBlock from './shared/getExportBlock.js';

export default function closure ( bundle, magicString, { exportMode, indentString, intro }, options ) {
	if ( exportMode !== 'none' && !options.moduleName ) {
		throw new Error( 'You must supply options.moduleName for Google Closure bundles' );
	}

	const deps = bundle.externalModules.map( quotePath );
	const args = bundle.externalModules.map( getName );

	const preamble = `goog.provide('${options.moduleName}');\n` +
				deps.map( dep => `goog.require(${dep});\n` ).join('');

	const lvalues = args.map(a => a.replace(/\./g, '$'));

	args.unshift(options.moduleName);
	lvalues.unshift('exports');

	const useStrict = options.useStrict !== false ? ` 'use strict';` : ``;

	const wrapperStart = `${preamble}\n\n(function (${lvalues.join( ', ' )}) {${useStrict}\n\n`;
	const wrapperEnd = `})(${args.join( ', ' )});`;

	// var foo__default = 'default' in foo ? foo['default'] : foo;
	const interopBlock = getInteropBlock( bundle );
	if ( interopBlock ) magicString.prepend( interopBlock + '\n\n' );

	if ( intro ) magicString.prepend( intro );

	const exportBlock = getExportBlock( bundle.entryModule, exportMode );
	if ( exportBlock ) magicString.append( '\n\n' + exportBlock );
	if ( options.outro ) magicString.append( `\n${options.outro}` );

	return magicString
		.indent( indentString )
		.prepend( wrapperStart )
		.append( wrapperEnd );
}