How can you copy an object in JavaScript? What methods do you know?

In JavaScript, there are several ways to copy an object:

1. Shallow copy:

   • Using Object.assign():

     const copy = Object.assign({}, original);
     

   • Spread operator:

     const copy = {...original};
     

   These methods only copy the first level of properties; nested objects remain references.

2. Deep copy:

   • Via JSON serialization:

     const deepCopy = JSON.parse(JSON.stringify(original));
     

     But this method does not copy functions, undefined, symbols, and does not work with cyclic references.

   • Using specialized libraries, such as lodash:

     const _ = require('lodash');
     const deepCopy = _.cloneDeep(original);
     

3. Recursive copying: You can write your own function for deep copying, traversing all nested objects.

The choice of method depends on the structure of the object and the copying requirements.