connectAdvanced

API > connectAdvanced: customizing connect for advanced behavior

connectAdvanced()

connectAdvanced(selectorFactory, connectOptions?)

Connects a React component to a Redux store. It is the base for connect() but is less opinionated about how to combine state, props, and dispatch into your final props. It makes no assumptions about defaults or memoization of results, leaving those responsibilities to the caller.

It does not modify the component class passed to it; instead, it returns a new, connected component class for you to use.

Most applications will not need to use this, as the default behavior in connect is intended to work for most use cases.

:::info

connectAdvanced was added in version 5.0, and connect was reimplemented as a specific set of parameters to connectAdvanced. However, connectAdvanced is now deprecated and will eventually be removed in a future major version of React Redux.

:::

Arguments

• selectorFactory(dispatch, factoryOptions): selector(state, ownProps): props (Function): Initializes a selector function (during each instance's constructor). That selector function is called any time the connector component needs to compute new props, as a result of a store state change or receiving new props. The result of selector is expected to be a plain object, which is passed as the props to the wrapped component. If a consecutive call to selector returns the same object (===) as its previous call, the component will not be re-rendered. It's the responsibility of selector to return that previous object when appropriate.

• [connectOptions] (Object) If specified, further customizes the behavior of the connector.

  • [getDisplayName] (Function): computes the connector component's displayName property relative to that of the wrapped component. Usually overridden by wrapper functions. Default value: name => 'ConnectAdvanced('+name+')'

  • [methodName] (String): shown in error messages. Usually overridden by wrapper functions. Default value: 'connectAdvanced'

  • [renderCountProp] (String): if defined, a property named this value will be added to the props passed to the wrapped component. Its value will be the number of times the component has been rendered, which can be useful for tracking down unnecessary re-renders. Default value: undefined

  • [shouldHandleStateChanges] (Boolean): controls whether the connector component subscribes to redux store state changes. If set to false, it will only re-render when parent component re-renders. Default value: true

  • [forwardRef] (Boolean): If true, adding a ref to the connected wrapper component will actually return the instance of the wrapped component.

  • Additionally, any extra options passed via connectOptions will be passed through to your selectorFactory in the factoryOptions argument.

Returns

A higher-order React component class that builds props from the store state and passes them to the wrapped component. A higher-order component is a function which accepts a component argument and returns a new component.

Static Properties

• WrappedComponent (Component): The original component class passed to connectAdvanced(...)(Component).

Static Methods

All the original static methods of the component are hoisted.

Remarks

• Since connectAdvanced returns a higher-order component, it needs to be invoked two times. The first time with its arguments as described above, and a second time, with the component: connectAdvanced(selectorFactory)(MyComponent).

• connectAdvanced does not modify the passed React component. It returns a new, connected component, that you should use instead.

Examples

Inject todos of a specific user depending on props, and inject props.userId into the action

import * as actionCreators from './actionCreators'
import { bindActionCreators } from 'redux'

function selectorFactory(dispatch) {
  let ownProps = {}
  let result = {}

  const actions = bindActionCreators(actionCreators, dispatch)
  const addTodo = (text) => actions.addTodo(ownProps.userId, text)

  return (nextState, nextOwnProps) => {
    const todos = nextState.todos[nextOwnProps.userId]
    const nextResult = { ...nextOwnProps, todos, addTodo }
    ownProps = nextOwnProps
    if (!shallowEqual(result, nextResult)) result = nextResult
    return result
  }
}
export default connectAdvanced(selectorFactory)(TodoApp)