/*
	MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const HelperRuntimeModule = require("./HelperRuntimeModule");

/** @import Compilation from "../Compilation" */

class SetAnonymousDefaultNameRuntimeModule extends HelperRuntimeModule {
	constructor() {
		super("set anonymous default export name");
	}

	/**
	 * Returns true, if the runtime module should get it's own scope.
	 * When false, `generate()` must emit complete statements ending with `;`
	 * so a following runtime IIFE is not parsed as a call (ASI).
	 * @returns {boolean} true, if the runtime module should get it's own scope
	 */
	shouldIsolate() {
		return false;
	}

	/**
	 * Generates runtime code for this runtime module.
	 * @returns {string | null} runtime code
	 */
	generate() {
		const compilation = /** @type {Compilation} */ (this.compilation);
		const { runtimeTemplate } = compilation;
		const fn = RuntimeGlobals.setAnonymousDefaultName;
		return Template.asString([
			"// set .name for anonymous default exports per ES spec",
			"// skipped when the property is non-configurable (pre-ES2015 engines),",
			"// where Object.defineProperty would throw",
			`${fn} = ${runtimeTemplate.basicFunction("x", [
				'var descriptor = Object.getOwnPropertyDescriptor(x, "name");',
				'if (!descriptor || (!descriptor.writable && descriptor.configurable)) Object.defineProperty(x, "name", { value: "default", configurable: true });'
			])};`
		]);
	}
}

module.exports = SetAnonymousDefaultNameRuntimeModule;