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What is immutability in JavaScript and why is it important?

Asked on Jul 30, 2025

Answer

Immutability in JavaScript refers to the concept where data structures cannot be altered after they are created. This is important for ensuring predictable code behavior, especially in functional programming and state management.

// Example of immutability with objects using Object.freeze
        const person = Object.freeze({
            name: "Alice",
            age: 30
        });

        // Attempting to modify the object will not change it
        person.age = 31; // This will have no effect

        console.log(person.age); // Outputs: 30

Additional Comment:

Immutability helps in avoiding side effects, making code easier to debug and test.
Using "Object.freeze" prevents modifications to the object properties.
Immutability is crucial in frameworks like React for efficient state management and rendering.
To update immutable data, you create a new object or array with the updated values.

✅ Answered with JavaScript best practices.

Ask any question about JavaScript here... and get an instant response.

What is immutability in JavaScript and why is it important?

Asked on Jul 30, 2025

Answer

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