chrome+firefox v0.3.1 Makefile and dist/ build/ folders

esbuild.config.mjs

@@ -35,12 +35,17 @@ const banner = `/*
 `;
 
 const prod = process.argv[2] === 'production';
-const outdir = 'build';
 
 // Target browser. Firefox and Chrome disagree on exactly one manifest key, so
 // the manifest is written per target rather than duplicated in the tree.
 const target = process.env.TARGET === 'chrome' ? 'chrome' : 'firefox';
 
+// Each target gets its own directory. They used to share one, and the result
+// was that whichever build ran last silently won: loading the other browser's
+// output then failed with a confusing manifest error. Separate directories
+// mean both can exist at once and neither can be stale by accident.
+const outdir = `build/${target}`;
+
 /**
  * Write the manifest for the target browser.
  *
@@ -60,8 +65,9 @@ async function writeManifest() {
 	);
 }
 
-// Everything that is not TypeScript is copied verbatim into build/, so that
-// the directory can be handed straight to about:debugging.
+// Everything that is not TypeScript is copied verbatim into the output, so
+// that the directory can be handed straight to about:debugging or to Chrome's
+// "Load unpacked".
 async function copyStatic() {
 	await mkdir(outdir, { recursive: true });
 	for (const name of await readdir('src')) {
@@ -76,7 +82,7 @@ async function copyStatic() {
 await copyStatic();
 
 // In watch mode the static files must follow every rebuild, otherwise editing
-// manifest.json or a .html file silently changes nothing in build/.
+// manifest.json or a .html file silently changes nothing in the output.
 const staticPlugin = {
 	name: 'copy-static',
 	setup(build) {