A naukri.com initiative
Medium
1M
359
Image Credit: Medium
Deep vs Shallow Copy Behavior in JavaScript
- When working with primitive types like numbers or strings, assigning a value results in a full copy being made in memory.
- In contrast, when dealing with objects and arrays in JavaScript, they are treated as references rather than copied entirely.
- Assigning an object or array to another variable copies the pointer to the data location, not the content itself.
- Shallow copies only copy the top layer, meaning inner objects remain shared if they are objects themselves.
- Tools like Object.assign and the spread syntax can be used to create shallow copies in JavaScript.
- Deep copies duplicate every nested object or array inside, ensuring no shared references are left.
- JSON.stringify and JSON.parse together can be used for simple deep copies, though not suitable for all data types.
- Issues may arise with shallow copies when internal objects are inadvertently shared, leading to unexpected behavior.
- JSON-based deep copying may lose data for functions, Date objects, Map, Set, BigInt, Symbol-keyed properties, or undefined values.
- Handling cyclic structures in copying requires special consideration to avoid infinite loops and data loss.
Read Full Article
21 Likes
For uninterrupted reading, download the app