this.forceUpdate（）重构withHandler

Question

I want to use this.forceUpdate() in one of the handler named 'update' in withHandlers of my compose. I am using recompose to achieve the same. Find sample code below:

const abc = compose(
    withHandlers(
      update: () => () => this.forceUpdate()
    )
)

But it is not working. Does anyone know how to use forceUpdate() method of react in withHandlers of recompose library?

Is there any alternative to achieve same result as forceUpdate() ?

Answer 1

You're using this outside of your component's scope, so this is undefined.

I don't know what do you want to achieve but you should try another way to do it.

Normally you should try to avoid all uses of forceUpdate()

Answer 2

There's forceUpdate in lifecycle.

We use it like this:

import { lifecycle } from 'recompose';

const listensForChangingModel = ( propName='model' ) => lifecycle( {
        componentDidMount() {
                this.onModelChanged = () => this.forceUpdate();

                this.props[ propName ].on( 'change', this.onModelChanged );
        },  
        componentWillUnmount() {
                this.props[ propName ].off( 'change', this.onModelChanged );
        },  
        componentDidUpdate( prevProps ) { 
                if ( prevProps[ propName ].cid !== this.props[ propName ].cid ) { 
                        prevProps[ propName ].off( 'change', this.onModelChanged );
                        this.props[ propName ].on( 'change', this.onModelChanged );
                }   
        },  
} );

export default listensForChangingModel;

This make a higher-order component that forces update when the model fires change event.

Answer 3

You can use withState to make your own props.forceUpdate , since all state updaters trigger the component to re-render.

IE:

withState('_forceUpdate', 'forceUpdate')

Then call props.forceUpdate() wherever.