use-loading-steps

A simple state management library for smooth react page loading experience.

Install

yarn add use-loading-steps
# or
npm install --save use-loading-steps

Usage

const [loadingState, setStepDone, resetLoading, skipStep] = useLoadingSteps(taskCount, initLoaded, options);

useLoadingSteps hook params

• taskCount: the number of steps should be done before the page is loaded.
• initLoaded: set to true to skip all state transitions, loadingState = DONE.
• options: see below.

Hook returns

• loadingState: the state, type: LState enum (string).
• setStepDone('step_name'): to be called when a step is finished, step_name should be a unique string.
• resetLoading(): to be called when reloading resources.
• skipStep('step_name): same effect as setStepDone, but prints different debug log.

Options

interface Options {
    renderDelay?: number; // timeout of SILENT_LOADING state after started
    resetDelay?: number;  // timeout of SILENT_LOADING state after reset
    doneDelay?: number;   // timeout of DELAY_DONE state
    name?: string;        // for debug log (useful if there are multiple pages / components use this hook)
}

The debug log is printed by console.debug, and is skipped in production build.

Loading States

export enum LState {
    SILENT_LOADING = 'SILENT_LOADING',  // for: do loading but not to show loading animation
    LOADING = 'LOADING',                // for: show loading animation
    DELAY_DONE = 'DELAY_DONE',          // for: loading finished but keep showing loading animation
    DONE = 'DONE',                      // for: all ready
}

Utility functions

export const isLoading = (state: LState) => LState.LOADING === state;
export const isReloading = (state: LState) => [LState.SILENT_LOADING, LState.LOADING].includes(state);
export const isDone = (state: LState) => LState.DONE === state;

Example

// Number of steps: 2, loaded: false, renderDelay: 100ms
const [loadingState, setStepDone] = useLoadingSteps(2, false, {renderDelay: 100});
const [rows, setRows] = useState([]);

useEffect(async () => {
  const data = await fetchData();
  setStepDone('fetch');
  
  const rows = await transformData(data);
  setStepDone('transform');
}, []);

if (isLoading(loadingState)) {
  return <div>(Loading animation)</div>; 
}
return (
  <div>
    {data.map((item) => <div>row: {item}</div>)}
  </div>
);

Explanation

• Initialize, if loaded = false, state => SILENT_LOADING, isLoading(loadingState) = false
• After 100ms, if not finished, state => LOADING, isLoading(loadingState) = true
• After the two setStepDone('step name') are called, state => DONE, isLoading(loadingState) = false

More examples

• Please refer to unit tests in lib/__test__.