built in webaudio prebake ?

package.json

@@ -10,6 +10,7 @@
     "snapshot": "cd repl && npm run snapshot",
     "repl": "cd repl && npm run dev",
     "osc": "cd packages/osc && npm run server",
+    "sampler": "cd ./repl/public/samples && node ../../packages/webaudio/sample-server.js",
     "build": "rm -rf out && cd repl && npm run build && cd ../tutorial && npm run build",
     "preview": "npx serve ./out",
     "deploy": "gh-pages -d out",

packages/webaudio/index.mjs

@@ -8,3 +8,4 @@ export * from './clockworker.mjs';
 export * from './scheduler.mjs';
 export * from './webaudio.mjs';
 export * from './sampler.mjs';
+export * from './prebake.mjs';

packages/webaudio/package.json

@@ -29,5 +29,10 @@
   "homepage": "https://github.com/tidalcycles/strudel#readme",
   "dependencies": {
     "@strudel.cycles/core": "^0.1.2"
+  },
+  "devDependencies": {
+    "koa": "^2.13.4",
+    "koa-static": "^5.0.0",
+    "@koa/cors": "^3.3.0"
   }
 }

packages/webaudio/prebake.mjs

@@ -0,0 +1,83 @@
+import { Pattern, toMidi } from '@strudel.cycles/core';
+import { samples } from '.';
+
+let baking;
+
+export function prebake(props) {
+  if (baking) {
+    return baking;
+  }
+  baking = prebaker(props);
+  return baking;
+}
+
+async function prebaker(props = {}) {
+  const { baseURL = './samples' } = props; // http://localhost:1234
+  try {
+    samples(
+      {
+        piano: {
+          A0: 'A0v8.mp3',
+          C1: 'C1v8.mp3',
+          Ds1: 'Ds1v8.mp3',
+          Fs1: 'Fs1v8.mp3',
+          A1: 'A1v8.mp3',
+          C2: 'C2v8.mp3',
+          Ds2: 'Ds2v8.mp3',
+          Fs2: 'Fs2v8.mp3',
+          A2: 'A2v8.mp3',
+          C3: 'C3v8.mp3',
+          Ds3: 'Ds3v8.mp3',
+          Fs3: 'Fs3v8.mp3',
+          A3: 'A3v8.mp3',
+          C4: 'C4v8.mp3',
+          Ds4: 'Ds4v8.mp3',
+          Fs4: 'Fs4v8.mp3',
+          A4: 'A4v8.mp3',
+          C5: 'C5v8.mp3',
+          Ds4: 'Ds4v8.mp3',
+          Fs5: 'Fs5v8.mp3',
+          A5: 'A5v8.mp3',
+          C6: 'C6v8.mp3',
+          Ds6: 'Ds6v8.mp3',
+          Fs6: 'Fs6v8.mp3',
+          A6: 'A6v8.mp3',
+          C7: 'C7v8.mp3',
+          Ds7: 'Ds7v8.mp3',
+          Fs7: 'Fs7v8.mp3',
+          A7: 'A7v8.mp3',
+          C8: 'C8v8.mp3',
+        },
+      },
+      // https://archive.org/details/SalamanderGrandPianoV3
+      // License: CC-by http://creativecommons.org/licenses/by/3.0/ Author: Alexander Holm
+      baseURL + '/piano/',
+    );
+
+    const maxPan = toMidi('C8');
+    const panwidth = (pan, width) => pan * width + (1 - width) / 2;
+
+    Pattern.prototype.piano = function () {
+      return this.clip(1)
+        .s('piano')
+        .fmap((value) => {
+          // pan by pitch
+          const pan = panwidth(Math.min(toMidi(value.note) / maxPan, 1), 0.5);
+          return { ...value, pan: (value.pan || 1) * pan };
+        });
+    };
+
+    // ping sample server
+    /* await fetch(samplerURL)
+      .then(() => {
+        console.log(`prebake: Using samples from "${baseURL}"`);
+      })
+      .catch(() => {
+        throw new Error(
+          `sample server not running at "${samplerURL}"... run "npm run sampler" from the strudel project root.`,
+        );
+      }); */
+  } catch (e) {
+    console.warn('prebake error', e);
+  }
+}

packages/webaudio/sample-server.js

@@ -0,0 +1,34 @@
+// "sampler": "cd ./repl/public/samples && node ../../../packages/webaudio/sample-server.js",
+// "sampler": "http-server ./repl/public",
+
+import fs from 'fs';
+import path from 'path';
+import Koa from 'koa'; // CJS: require('koa');
+import cors from '@koa/cors';
+import serve from 'koa-static'; // CJS: require('koa-static')
+const cwd = process.cwd();
+const yellow = '\x1b[33m%s\x1b[0m';
+
+// get array of all folders in cwd:
+const banks = fs.readdirSync(cwd).filter((f) => fs.statSync(path.join(cwd, f)).isDirectory());
+const app = new Koa();
+
+app.use(cors());
+app.use(serve(cwd));
+app.use((ctx, next) => {
+  return next().then(() => {
+    if (ctx.path === '/') {
+      ctx.body = 'banks: ' + banks.join(', ');
+    }
+  });
+});
+const port = 1234;
+app.listen(port);
+
+console.log(yellow, `strudel sampler running at http://localhost:${port}`);
+
+// node: get current working directory
+console.log(yellow, 'cwd: ' + cwd);
+
+console.log('found banks:');
+banks.map((c) => console.log(yellow, c));