apps/docs: math/decibels

apps/docs/src/utils/math/decibels.test.ts

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+import {describe, expect, it} from 'vitest';
+import {gainToDecibels, dbMin} from './decibels';
+
+describe('gainToDecibels', () => {
+  it('should convert gain to decibels correctly', () => {
+    expect(gainToDecibels(10)).toBeCloseTo(20.0);
+    expect(gainToDecibels(2)).toBeCloseTo(6.02);
+    expect(gainToDecibels(1)).toBeCloseTo(0);
+    expect(gainToDecibels(0.5)).toBeCloseTo(-6.02);
+    expect(gainToDecibels(0.25)).toBeCloseTo(-12.04);
+    expect(gainToDecibels(0.125)).toBeCloseTo(-18.06);
+    expect(gainToDecibels(0.01)).toBeCloseTo(-40);
+    expect(gainToDecibels(0.001)).toBeCloseTo(-60);
+  });
+
+  it(`should return ${dbMin} for extremely low values`, () => {
+    expect(gainToDecibels(1e-10)).toBeCloseTo(dbMin);
+    expect(gainToDecibels(1e-20)).toBeCloseTo(dbMin);
+    expect(gainToDecibels(1e-30)).toBeCloseTo(dbMin);
+    expect(gainToDecibels(1e-40)).toBeCloseTo(dbMin);
+    expect(gainToDecibels(0)).toBeCloseTo(dbMin);
+  });
+});

apps/docs/src/utils/math/decibels.ts

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+export const dbMin = -96;
+
+export const gainToDecibels = (gain: number): number => {
+  let res = 20 * Math.log10(gain);
+  res = Number.isFinite(res) ? res : dbMin;
+  res = Math.max(res, dbMin);
+  return res;
+};