react-async-states-utils v2.0.0-alpha-7

Utilities on top of react-async-states

React async states utils

Utilities for react-async-states.

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State Boundary

What is this ?

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State boundary is a component that allows performing all render strategies in react:

1. Render Then Fetch: Render the initial component, then fetch its data
2. Fetch As You Render: fetch data while rendering and suspend when pending and throw when error.
3. Fetch Then Render: renders nothing until it fetches data, suppressing the pending state.

StateBoundaryProps

This component accepts the following props:

Where the RenderStrategy enum is defined as follows:

export enum RenderStrategy {
FetchAsYouRender = 0,
FetchThenRender = 1,
RenderThenFetch = 2,
}

useCurrentState()

This hook returns the current state in the boundary

useBoundary(sourceKey?: string)

When Multiple StateBoundary are nested, this hook allows you to take any state up in the tree by its key.

This hook then calls useSource on the result obtained from the config given to that state boundary.

addBooleanStatus

This selector can be passed to useAsyncState, and will add the following properties to the existing state:

isInitial, isPending, isError, isAborted, isSuccess.

These properties are intuitive and well typed along with the equivalent status:

  type User = { username: string, password: string };

  function producer(props: ProducerProps<User, Error, "Timeout">): Promise<User> {
    if (!props.args[0]) throw new Error("username or password is incorrect");
    return Promise.resolve({username: 'admin', password: 'admin'});
  }

  let {state, runc} = useAsyncState({producer, selector: defaultSelector});

  if (state.isPending) {
    let {data} = state; // type of data: null
  }
  if (state.isError) {
    let {data} = state; // type of data: Error
  }
  if (state.isAborted) {
    let {data} = state; // type of data: "Timeout"
  }

  if (state.status === Status.initial) {
    let data = state.data; // ts type of data <- User | undefined
    let {isError, isSuccess} = state;
    if (isSuccess) { // <- type of isSuccess is false
      console.log("impossible")
    }
    if (isError) {  // <- type of isError is false
      console.log('impossible')
    }
  }
  if (state.status === Status.pending) {
    let data = state.data; // ts type of data <- null
  }
  if (state.status === Status.success) {
    let data = state.data; // ts type of data <- User
  }
  if (state.status === Status.error) {
    let data = state.data; // ts type of data <- Error
  }
  if (state.status === Status.aborted) {
    let data = state.data; // ts type of data <- "Timeout"
  }