esbuild: add watching

package.json

@@ -5,7 +5,8 @@
 	"main": "src/index.mjs",
 	"scripts": {
 		"test": "echo \"No tests have been written yet.\"",
-		"build": "node ./src/esbuild.mjs"
+		"build": "node ./src/esbuild.mjs",
+		"watch": "ES_MODE=\"watch\" node ./src/esbuild.mjs"
 	},
 	"repository": {
 		"type": "git",

src/esbuild.mjs

@@ -57,10 +57,8 @@ async function do_html() {
 	}
 }
 
-(async () => {
-	"use strict";
-	
-	const result = await esbuild.build({
+function make_context() {
+	return {
 		entryPoints: [
 			"./app.mjs",
 			"./app.css",
@@ -79,10 +77,37 @@ async function do_html() {
 			".ttf": "file",
 		},
 		external: ["fs", "path"],
-	});
+		plugins: [
+			{
+				name: "copy-html",
+				setup(build) {
+					build.onEnd(_result => {
+						do_html();
+					})
+				}
+			}
+		]
+	};
+}
+
+(async () => {
+	"use strict";
+	switch(process.env.ES_MODE ?? "build") {
+		case "build":
+			const result = await esbuild.build(make_context());
 			if (result.errors.length > 0 || result.warnings.length > 0)
 				console.log(result);
+			break;
 		
-	await do_html();
+		case "watch":
+			const ctx = await esbuild.context(make_context());
+			await ctx.watch();
+			console.log(`>>> Watching for changes`);
+			break;
+	}
+	
+	
+	// await do_html();
 	// console.log(await esbuild.analyzeMetafile(result.metafile));
 })();
+