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  • License MIT

Opinionated state management

Package Exports

  • subjective

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (subjective) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Subjective

  • Opinionated state management
  • Type safety by design. Type inference works for both Update and Selector functions.
  • Logging. Inspect where Update function was called.
  • Pause observable stream, if needed.
  • Always receive the whole state, if needed.

Concepts

State

const state = new Subjective(
    productState,
    productStateFns,
);
Default Logger
const state = new Subjective(
    productState,
    productStateFns,
    // use default Logger (dev only)
    true
);
Custom Logger
const state = new Subjective(
    productState,
    productStateFns,
    // use custom Logger (dev only)
    (updateFnName: string, payload: any, updateFnRef: Function) => {
        // LOG
        const data = JSON.stringify(payload);
        const dataTrimmed = data.substring(0, 80);
        // logging to console
        console.groupCollapsed(
            `%c${fnName}: %c${dataTrimmed}${
                dataTrimmed.length < data.length ? '…' : ''
            }`,
            `color: green; font-weight: 300;`,
            `color: gray; font-weight: 100;`,
        );
        console.log(payload);
        console.log(updateFnRef);
        console.groupEnd();
    }
);

EXAMPLE

Selector function

Subscribe to state.filter.type and notify with its value
state.select(s => s.filter.type).subscribe();
Subscribe to state.filter.type and notify with a whole state
state.select(s => s.filter.type, true).subscribe();

EXAMPLE

Update function

Update value of state.filter.type
state.update(f => f.updateFilterType, type);
Update value of state.filter.type and do not notify subscribers
state.update(f => f.updateFilterType, type, false);
Update value of state.filter.type and return updated state
const updatedState = state.update(f => f.updateFilterType, type);

EXAMPLE

Examples

NOTES

Immutable pattern

Always use immutable pattern otherwise it will not work. We can't rely on mutations since object reference is always the same.

Type-safety

Types are always inferred either from state class or payload parameter of the update function.

FUTURE

I've been thinking of this new syntax...check it out.

Credits