Replace value

After you specify the path to find the target node, you can use the update function to replace the target node with a new value.

const newObj = update(obj, 'artists[0].albums[id=2].year', 1998);
// newObj = {
//   ...,
//   artists: [
//     {
//       ...,
//       albums: [
//         { id: 1, ... },
//         { id: 2, name: 'a2', year: 1998 }
//       ]
//     }
//   ]
// }

The newObj is a new object with the target node updated, obj is untouched.

Replace object

If the target node is an object, the new value will replace the whole object at the target node.

newObj = update(obj, 'options.albums', { showId: false, sortBy: 'year' });
// newObj = {
//   options: {
//     albums: {
//       showId: false,
//       sortBy: 'year'
//     }
//   },
//   ...
// }

Merge object

When isMerge is true and the target node is an object, the properties of the new object will be merged into the old one.

newObj = update(obj, 'artists[id=3].albums[name=a2]', { year: 2000, rate: 95 }, null, true);
// newObj = {
//   ...,
//   artists: [
//     {
//       ...,
//       albums: [
//         { id: 1, ... },
//         { id: 2, name: 'a2', year: 2000, rate: 95 }
//       ]
//     }
//   ]
// }

Add element to an array

If the target is an array, and you put a "[]" after the name of the array in the path, it means you want to add a new element to the end of the array:

let newAlbum = { id: 3, name: 'a3', year: 2000 }
newObj = update(obj, 'artists[0].albums[]', newAlbum);
// newObj = {
//   ...,
//   artists: [
//     {
//       ...,
//       albums: [
//         { id: 1, ... },
//         { id: 2, ... },
//         { id: 3, name: 'a3', year: 2000 }
//       ]
//     }
//   ]
// }

Remove element from an array

If the target is an array element, and the new value is null, it means you want to remove that element from an array:

newObj = update(obj, 'artists[0].albums[name=a2]', null);
// newObj = {
//   ...,
//   artists: [
//     {
//       ...,
//       albums: [
//         { id: 1, ... }
//       ]
//     }
//   ]
// }

Missing nodes

If an array or object doesn't exist along the path, it will be created.

let newConcert = { id: 1, name: 'c1', date: new Date(2018, 1, 5) }
newObj = update(obj, 'artists[0].concerts[]', newConcert);
// newObj = {
//   ...,
//   artists: [
//     {
//       ...,
//       albums: [ ... ],
//       concerts: [
//         { id: 1, name: 'c1', ... }
//       ]
//     }
//   ]
// }