Member-only story
Source: Mutable and Immutable in JavaScript
For more questions and answers visit our website at Frontend Interview Questions
In JavaScript, mutable and immutable refer to the state of an object or value, and whether or not that state can be changed.
An object or value is considered mutable if its internal state can be changed after it has been created. This means that the value can be updated or modified in-place, and any references to that value will reflect the updated state. Examples of mutable types in JavaScript include objects and arrays.
On the other hand, an object or value is considered immutable if its internal state cannot be changed after it has been created. This means that the value cannot be updated or modified in-place, and any attempt to do so will result in a new value being created instead. Examples of immutable types in JavaScript include strings, numbers, and booleans.
The distinction between mutable and immutable is important in functional programming, as immutable data is preferred over mutable data, since it simplifies program state management and helps to avoid bugs that can arise from unintended changes to mutable data. In JavaScript, libraries like Immutable.js provide support for immutable data structures.