How to Correctly Update Nested State Properties in React?

Modifying Nested State Properties in React

Nested state properties provide a logical organization for complex state structures in React. However, attempting to update these properties directly using this.setState does not produce the desired outcome.

Solution:

To correctly update nested state properties, follow these steps to preserve the state's immutability:

1. Create a Copy:

   • Copy the nested property into a new variable using the spread operator, e.g., var someProperty = {...this.state.someProperty}.

2. Modify the Copy:

   • Make the necessary changes to the copied property, e.g., someProperty.flag = true.

3. Update the State:

   • Update the component's state by setting it to the modified copy, e.g., this.setState({someProperty}).

For Highly Nested States:

If the state is deeply nested, it is impractical to use the spread operator at each level. Consider using the immutability-helper package for more elegant updates:

this.setState(prevState => ({
  ...prevState,
  someProperty: {
    ...prevState.someProperty,
    someOtherProperty: {
      ...prevState.someProperty.someOtherProperty,
      anotherProperty: {
        ...prevState.someProperty.someOtherProperty.anotherProperty,
        flag: false
      }
    }
  }
}));

Immutability-Helper:

The immutability-helper package provides a more concise and intuitive syntax for updating nested state properties:

import {update} from "immutability-helper";
this.setState(update(this.state, {
  someProperty: {
    someOtherProperty: {
      anotherProperty: {
        flag: {$set: false}
      }
    }
  }
}));

The above is the detailed content of How to Correctly Update Nested State Properties in React?. For more information, please follow other related articles on the PHP Chinese website!