From d5c2ac07f89669beefccc58cb27dce7b95d36cfc Mon Sep 17 00:00:00 2001
From: Momtchil Momtchev <momtchil@momtchev.com>
Date: Tue, 8 Sep 2020 13:19:44 +0200
Subject: [PATCH] experimental mjs loader for Node 14

---
 lib/hbs-es-loader.mjs | 72 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 lib/hbs-es-loader.mjs

diff --git a/lib/hbs-es-loader.mjs b/lib/hbs-es-loader.mjs
new file mode 100644
index 000000000..610d0e4f3
--- /dev/null
+++ b/lib/hbs-es-loader.mjs
@@ -0,0 +1,72 @@
+/**
+ * This is an experimental automatic precompiler for
+ * ECMAScript Modules in Node.js (aka the Michael Jackson Solution)
+ * 
+ * 
+ * usage:
+ * 
+ * node --experimental-loader handlebars/lib/hbs-es-loader.mjs index.js
+ * 
+ * or
+ * 
+ * export NODE_OPTIONS="--experimental-loader handlebars/lib/hbs-es-loader.mjs"
+ * node index.js
+ * 
+ * 
+ * then import the template and use it as a function:
+ * 
+ * import tmpl from '../handlebars/email-alert.handlebars';
+ * const text = tmpl({});
+ */
+
+import * as path from 'path';
+import handlebars from 'handlebars';
+
+/**
+ * @param {string} url
+ * @param {Object} context (currently empty)
+ * @param {Function} defaultGetFormat
+ * @returns {Promise<{ format: string }>}
+ */
+export async function getFormat(url, context, defaultGetFormat) {
+	try {
+		const ext = path.extname(url);
+		if (ext === '.hbs' || ext === '.handlebars') {
+			return {
+				format: 'module'
+			};
+		}
+	} catch (e) {
+		console.log(e);
+	}
+	// Defer to Node.js for all other URLs.
+	return defaultGetFormat(url, context, defaultGetFormat);
+}
+
+
+/**
+ * @param {!(string | SharedArrayBuffer | Uint8Array)} source
+ * @param {{
+ *   format: string,
+ *   url: string,
+ * }} context
+ * @param {Function} defaultTransformSource
+ * @returns {Promise<{ source: !(string | SharedArrayBuffer | Uint8Array) }>}
+ */
+const _header = 'import handlebars from "handlebars"; const _template = handlebars.template(';
+const _footer = '); export default _template;'
+export async function transformSource(source, context, defaultTransformSource) {
+	const { url, format } = context;
+	try {
+		const ext = path.extname(url);
+		if (format === 'module' && (ext === '.hbs' || ext === '.handlebars')) {
+			return {
+				source: _header + handlebars.precompile(source.toString()) + _footer
+			}
+		}
+	} catch (e) {
+		console.log(e);
+	}
+	// Defer to Node.js for all other sources.
+	return defaultTransformSource(source, context, defaultTransformSource);
+}
\ No newline at end of file