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Performance

Mutative is a high-performance immutable data structure library, it is up to 2x-6x faster than naive handcrafted reducer and up to 16x faster than Immer.

Mutative vs Reducer Performance​

Reducer by object​

  • Naive handcrafted reducer
// baseState type: Record<string, { value: number }>
const state = {
  ...baseState,
  key0: {
    ...baseState.key0,
    value: i,
  },
};
  • Mutative
const state = create(baseState, (draft) => {
  draft.key0.value = i;
});

Mutative vs Reducer benchmark by object

Measure(seconds) to update the 1K-100K items object, lower is better(view source).

Mutative is up to 2x faster than naive handcrafted reducer for updating immutable objects.

Reducer by array​

  • Naive handcrafted reducer
// baseState type: { value: number }[]
const state = [
  { ...baseState[0], value: i },
  ...baseState.slice(1, baseState.length),
];
  • Mutative
const state = create(baseState, (draft) => {
  draft[0].value = i;
});

Mutative vs Reducer benchmark by array

Measure(seconds) to update the 1K-100K items array, lower is better(view source).

Mutative is up to 6x faster than naive handcrafted reducer for updating immutable arrays.

Mutative vs Immer Performance​

Mutative passed all of Immer's test cases.

Measure(ops/sec) to update 50K arrays and 1K objects, bigger is better(view source). [Mutative v1.0.5 vs Immer v10.1.1]

Benchmark

Naive handcrafted reducer - No Freeze x 4,442 ops/sec ±0.38% (95 runs sampled)
Mutative - No Freeze x 6,199 ops/sec ±0.79% (89 runs sampled)
Immer - No Freeze x 5.30 ops/sec ±0.38% (18 runs sampled)

Mutative - Freeze x 974 ops/sec ±1.77% (92 runs sampled)
Immer - Freeze x 376 ops/sec ±0.67% (92 runs sampled)

Mutative - Patches and No Freeze x 969 ops/sec ±0.99% (97 runs sampled)
Immer - Patches and No Freeze x 5.27 ops/sec ±0.36% (18 runs sampled)

Mutative - Patches and Freeze x 514 ops/sec ±0.97% (95 runs sampled)
Immer - Patches and Freeze x 275 ops/sec ±0.74% (89 runs sampled)

The fastest method is Mutative - No Freeze

Run yarn benchmark to measure performance.

OS: macOS 14.2.1, CPU: Apple M1 Max, Node.js: v20.11.0

Immer relies on auto-freeze to be enabled, if auto-freeze is disabled, Immer will have a huge performance drop and Mutative will have a huge performance lead, especially with large data structures it will have a performance lead of more than 50x.

So if you are using Immer, you will have to enable auto-freeze for performance. Mutative is disabled auto-freeze by default. With the default configuration of both, we can see the 16x performance gap between Mutative (6,199 ops/sec) and Immer (376 ops/sec).

Overall, Mutative has a huge performance lead over Immer in more performance testing scenarios. Run yarn performance to get all the performance results locally.