Improve float precision handling in fader parameter extraction and add corresponding test case

src/lib/parsers.ts

@@ -560,13 +560,11 @@ export function collectSettings(files: TarFile[]): ProjectSettings {
     for (let paramNum = 0; paramNum <= 11; paramNum++) {
       faderParamsData[groupId] = {
         ...faderParamsData[groupId],
-        [paramNum]: Number(
+        [paramNum]: bytesToFloat32(
-          bytesToFloat32(
           settings.data.slice(
             24 + groupNum * 48 + paramNum * 4,
             28 + groupNum * 48 + paramNum * 4,
           ),
-          ).toFixed(2),
         ),
       };
     }

tests/project-settings.test.ts

@@ -0,0 +1,35 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { collectSettings } from '../src/lib/parsers';
+import { TarFile } from '../src/lib/untar';
+import { FaderParam } from '../src/types/types';
+
+test('preserves float32 precision for every group fader parameter', () => {
+  const data = new Uint8Array(224);
+  const view = new DataView(data.buffer);
+  const expectedValues = new Map<string, number>();
+
+  view.setFloat32(4, 123.456789, true);
+
+  for (let groupNum = 0; groupNum < 4; groupNum++) {
+    for (let paramNum = 0; paramNum <= 11; paramNum++) {
+      const value = 0.1234567 + groupNum * 0.1 + paramNum * 0.0032109;
+      const offset = 24 + groupNum * 48 + paramNum * 4;
+      view.setFloat32(offset, value, true);
+      expectedValues.set(`${groupNum}:${paramNum}`, view.getFloat32(offset, true));
+    }
+  }
+
+  const settings = collectSettings([new TarFile('settings', data.length, data)]);
+
+  assert.equal(settings.bpm, 123.46);
+
+  for (const [groupNum, group] of ['a', 'b', 'c', 'd'].entries()) {
+    for (let paramNum = 0; paramNum <= 11; paramNum++) {
+      assert.equal(
+        settings.groupFaderParams[group][paramNum as FaderParam],
+        expectedValues.get(`${groupNum}:${paramNum}`),
+      );
+    }
+  }
+});