Add initial support for minifying in production (#19)

* Add initial support for minifying in production

* Prettier

* Don't minify when passed --no-minify

Co-Authored-By: Jake Deichert <git@jakedeichert.com>

* set module: true to terser for better minification

* format

* add minifed test results

* add yarn.lock to .gitignore

Co-authored-by: Jake Deichert <git@jakedeichert.com>

.gitignore

@@ -20,6 +20,7 @@ lib
 # node
 #######################################
 package-lock.json
+yarn.lock
 
 # Logs
 logs

package.json

@@ -20,7 +20,8 @@
     "chokidar": "^3.3.1",
     "glob": "^7.1.6",
     "p-limit": "^2.2.2",
-    "snowpack": "^1.0.5"
+    "snowpack": "^1.0.5",
+    "terser": "^4.6.3"
   },
   "devDependencies": {
     "@jakedeichert/eslint-config": "^4.0.5",

src/index.ts

@@ -7,6 +7,7 @@ import * as svelte from 'svelte/compiler';
 import * as chokidar from 'chokidar';
 import * as babel from '@babel/core';
 import * as glob from 'glob';
+import * as Terser from 'terser';
 import pLimit from 'p-limit';
 
 const exec = util.promisify(execSync);
@@ -82,6 +83,25 @@ async function transform(destPath: string): Promise<void> {
     }
 }
 
+// Minify file with terser.
+async function minify(destPath: string): Promise<void> {
+    try {
+        const source = await fs.readFile(destPath, 'utf8');
+
+        const result = Terser.minify(source, {
+            module: true,
+        });
+
+        await fs.writeFile(destPath, result.code);
+        console.info(`Terser minified ${destPath}`);
+    } catch (err) {
+        console.log('');
+        console.error(`Failed to minify with terser: ${destPath}`);
+        console.error(err);
+        console.log('');
+    }
+}
+
 // Only needs to run during the initial compile cycle. If a developer adds a new package dependency,
 // they should restart svelvet.
 const snowpack = async (): Promise<void> => {
@@ -149,6 +169,18 @@ async function initialBuild(): Promise<void> {
             })
         )
     );
+
+    // Minify js files with terser if in production.
+    if (IS_PRODUCTION_MODE && !process.argv.includes('--no-minify')) {
+        await Promise.all(
+            destFiles.map(destPath =>
+                concurrencyLimit(async () => {
+                    if (!destPath) return;
+                    await minify(destPath);
+                })
+            )
+        );
+    }
 }
 
 function startWatchMode(): void {

tests/snapshot/dist/components/Footer/Links.js

@@ -1,41 +1,31 @@
-/* generated by Svelte v3.17.2 */
 import {
-    SvelteComponent,
-    detach,
-    element,
-    init,
-    insert,
-    noop,
-    safe_not_equal,
+    SvelteComponent as e,
+    detach as t,
+    element as n,
+    init as r,
+    insert as o,
+    noop as s,
+    safe_not_equal as l,
 } from '/web_modules/svelte/internal.js';
-
-function create_fragment(ctx) {
-    let nav;
+function u(e) {
+    let r;
     return {
         c() {
-            nav = element('nav');
-            nav.innerHTML = `<a href="/">Home</a>`;
+            (r = n('nav')), (r.innerHTML = '<a href="/">Home</a>');
         },
-
-        m(target, anchor) {
-            insert(target, nav, anchor);
+        m(e, t) {
+            o(e, r, t);
         },
-
-        p: noop,
-        i: noop,
-        o: noop,
-
-        d(detaching) {
-            if (detaching) detach(nav);
+        p: s,
+        i: s,
+        o: s,
+        d(e) {
+            e && t(r);
         },
     };
 }
-
-class Component extends SvelteComponent {
-    constructor(options) {
-        super();
-        init(this, options, null, create_fragment, safe_not_equal, {});
+export default class extends e {
+    constructor(e) {
+        super(), r(this, e, null, u, l, {});
     }
 }
-
-export default Component;