lib/src/util/support/Rehydratable.ts

/**
 * Type representing a JSON serializable object.
 */
import {ErrorWithContext} from '../error/ErrorWithContext'
import {Awaitable} from './types'

export type JSONState = { [key: string]: string | boolean | number | undefined | JSONState | Array<string | boolean | number | undefined | JSONState> }

/**
 * An error thrown when the state passed into a class is invalid for that class.
 */
export class InvalidJSONStateError extends ErrorWithContext {}

/**
 * Returns true if the given object can be JSON serialized.
 * @param what
 * @return boolean
 */
export function isJSONState(what: unknown): what is JSONState {
    try {
        JSON.stringify(what)
        return true
    } catch (e) {
        return false
    }
}

/**
 * Base interface for a class that can be rehydrated and restored.
 */
export interface Rehydratable {
    /**
     * Dehydrate this class' state and get it.
     * @return JSONState|Promise<JSONState>
     */
    dehydrate(): Awaitable<JSONState>

    /**
     * Rehydrate a state into this class.
     * @param {JSONState} state
     * @return void|Promise<void>
     */
    rehydrate(state: JSONState): Awaitable<void>
}