async-property

Simple typesafe helper to store async operations state and data.

Example

To work with async processes in react and redux we use async types and actions, so why not to use async properties.

import React, { useState, useEffect } from 'react'
import {
  AsyncProperty,
  emptyProperty, requestProperty,
  setSuccessProperty, setFailureProperty,
  isEmpty, isRequest, isSuccess, isFailure
} from 'async-property';
const requestStringProperty = async () => new Promise<string>((resolve) => resolve('async result'))
const Example: React.FC = () => {
  const [stringProperty, setStringProperty] = useState<AsyncProperty<string>>(emptyProperty)
  useEffect(() => {
    setStringProperty(requestProperty)
    const fetchData = async () => {
      try {
        const stringResult = await requestStringProperty()
        setStringProperty(setSuccessProperty(stringResult))
      } catch (error) {
        setStringProperty(setFailureProperty(error))
      }
    }
    fetchData()
  }, [])
  if (isEmpty(stringProperty) || isRequest(stringProperty)) {
    return (
      <p>Processing</p>
    )
  }
  if (isFailure(stringProperty)) {
    return (
      <p>Failure: {stringProperty.error}</p>
    )
  }
  if (isSuccess(stringProperty)) {
    return (
      <p>Success: {stringProperty.value}</p>
    )
  }
  return <p>Initialize</p>
}

Documentation

Types

type AsyncProperty<T, F = Error> = EmptyProperty | RequestProperty | SuccessProperty<T> | FailureProperty<F> | CancelProperty;
type EmptyProperty = {
    state: PropertyState.EMPTY
}
type RequestProperty = {
    state: PropertyState.REQUEST
}
type SuccessProperty<T> = {
    state: PropertyState.SUCCESS,
    value: T,
}
type FailureProperty<T = Error> = {
    state: PropertyState.FAILURE,
    error: T,
}
type CancelProperty = {
    state: PropertyState.CANCEL,
    reason?: string,
}

Enum

const enum PropertyState {
    EMPTY = 'Empty',
    REQUEST = 'Request',
    SUCCESS = 'Success',
    FAILURE = 'Failure',
    CANCEL = 'Cancel',
}

Constants

const emptyProperty: EmptyProperty = {
    state: PropertyState.EMPTY
}
const requestProperty: RequestProperty = {
    state: PropertyState.REQUEST
}
const cancelProperty: CancelProperty = {
    state: PropertyState.CANCEL
}

Methods

Setters

function setSuccessProperty<T>(value: T): SuccessProperty<T>
function setFailureProperty<T>(error: T): FailureProperty<T>
function setCancelProperty(reason: string): CancelProperty

Type check

function isAsyncProperty<T, F>(property: any): property is AsyncProperty<T, F>
function isEmpty(property: AsyncProperty<any>): property is EmptyProperty
function isRequest(property: AsyncProperty<any>): property is RequestProperty
function isSuccess<T>(property: AsyncProperty<T>): property is SuccessProperty<T>
function isFailure<T>(property: AsyncProperty<any, T>): property is FailureProperty<T>
function isCancel(property: AsyncProperty<any>): property is CancelProperty

Contribute

Build

npm run build

Test

npm test