set

The set method for the Map store allows you to update or create a value for a specific key in the store.

key(mapKey: string).set(value: T, notify: boolean = true): void

Parameters

Returns

void

Description

The set method updates or creates a value for a specific key in the Map store. It's accessed through the key method of the store, which allows you to specify the key you want to operate on. This design is particularly useful for stores where you have a repeating structure for each item.

Important Note: If the key doesn't exist in the store, set will create it. If it does exist, it will overwrite the entire value for that key.

Example

import { createMapStore } from '@devlab/store';
 
type UserData = {
  name: string;
  age: number;
  preferences: {
    theme: 'light' | 'dark';
  };
};
 
const userStore = createMapStore<UserData>({
  initialData: new Map([
    ['user1', { name: 'John Doe', age: 30, preferences: { theme: 'light' } }]
  ])
});
 
// Set a new user
userStore.key('user2').set({
  name: 'Jane Doe',
  age: 28,
  preferences: { theme: 'dark' }
});
 
// Update an existing user
userStore.key('user1').set({
  name: 'John Smith',
  age: 31,
  preferences: { theme: 'light' }
});
 
// Set without notifying subscribers
userStore.key('user3').set({
  name: 'Alice Johnson',
  age: 35,
  preferences: { theme: 'light' }
}, false);
 
// Usage in a React component
function UserProfile({ userId }: { userId: string }) {
  const userData = userStore.key(userId).use();
 
  return (
    <div>
      <p>Name: {userData.name}</p>
      <p>Age: {userData.age}</p>
      <p>Theme: {userData.preferences.theme}</p>
      <button onClick={() => userStore.key(userId).set({
        ...userData,
        age: userData.age + 1
      })}>
        Increment Age
      </button>
    </div>
  );
}

This example demonstrates how to use the set method to add new users and update existing ones in the Map store, as well as how to use it within a React component.

Differences from Object Store

Unlike the object store's set method, the Map store's set method:

1. Operates on a specific key in the Map, rather than a nested path.
2. Replaces the entire value for a key, rather than updating nested properties individually.
3. Is accessed through the key method, which provides a fluent interface for working with specific Map entries.

These differences make the Map store particularly suitable for collections of items with a consistent structure, where each item is identified by a unique key.