Regular JavaScript arrays are flexible but carry real overhead — Typed Arrays trade that flexibility for raw performance and predictable memory layout, genuinely useful for numeric, performance-critical code.
// Regular array: can hold anything, each element boxed with type info
const regular = [1, 2, 3, 'four', { five: 5 }];
// Typed array: fixed type, fixed size, contiguous memory - like a C array
const floats = new Float32Array(1000);
const ints = new Int32Array([1, 2, 3, 4, 5]);
floats[0] = 3.14;
// floats[0] = "not a number"; // silently coerced or becomes NaN, no error
// Real-world use: processing binary data (audio, images, network buffers)
const buffer = new ArrayBuffer(16);
const view = new Uint8Array(buffer);
Why the Performance Difference Is Real
A regular array’s elements can be any type, so the engine can’t assume a fixed size or layout in memory. Typed arrays guarantee a single, fixed-size type per element, letting the engine store them as truly contiguous memory — closer to a raw C array — which is exactly why they’re the standard choice for WebGL, audio processing, and any code manipulating large binary buffers.