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Working with Data

Immutable Update Patterns

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The Art of Not Mutating

In modern JavaScript development, especially within frameworks like React and state management libraries like Redux, immutability is a core principle. Instead of modifying objects or arrays in place, we create new copies with the desired changes. This ensures predictable data flow and easier change detection.

1. Object Updates with Spread

The spread syntax (...) is the standard way to create a shallow copy of an object while overriding specific properties.

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2. Immutable Array Operations

Avoid methods like push, pop, or splice that mutate. Instead, use spread syntax and methods that return new arrays like map and filter.

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3. Deep Updates and structuredClone

Updating deeply nested data requires spreading at every level, which can become verbose.

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For a true deep copy (detaching all references), modern JS offers structuredClone(). Note that this clones the entire structure, which may be slower than targeted spreads for massive objects.

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