redux-devtools/extension/src/app/api/importState.ts

import jsan from 'jsan';
import { immutableSerialize } from '@redux-devtools/serialize';
import {
  Config,
  SerializeWithImmutable,
} from '../../browser/extension/inject/pageScript';
import Immutable from 'immutable';
import { LiftedState } from '@redux-devtools/instrument';
import { Action } from 'redux';

interface SerializeWithRequiredImmutable extends SerializeWithImmutable {
  readonly immutable: typeof Immutable;
}

function isSerializeWithImmutable(
  serialize: boolean | SerializeWithImmutable
): serialize is SerializeWithRequiredImmutable {
  return !!(serialize as SerializeWithImmutable).immutable;
}

interface SerializeWithRequiredReviver extends SerializeWithImmutable {
  readonly reviver: (key: string, value: unknown) => unknown;
}

function isSerializeWithReviver(
  serialize: boolean | SerializeWithImmutable
): serialize is SerializeWithRequiredReviver {
  return !!(serialize as SerializeWithImmutable).immutable;
}

interface ParsedSerializedLiftedState {
  readonly payload: string;
  readonly preloadedState?: string;
}

export default function importState<S, A extends Action<unknown>>(
  state: string | undefined,
  { serialize }: Config
) {
  if (!state) return undefined;
  let parse = jsan.parse;
  if (serialize) {
    if (isSerializeWithImmutable(serialize)) {
      parse = (v) =>
        jsan.parse(
          v,
          immutableSerialize(
            serialize.immutable,
            serialize.refs,
            serialize.replacer,
            serialize.reviver
          ).reviver
        );
    } else if (isSerializeWithReviver(serialize)) {
      parse = (v) => jsan.parse(v, serialize.reviver);
    }
  }

  const parsedSerializedLiftedState:
    | ParsedSerializedLiftedState
    | LiftedState<S, A, unknown> = parse(state) as
    | ParsedSerializedLiftedState
    | LiftedState<S, A, unknown>;
  let preloadedState =
    'payload' in parsedSerializedLiftedState &&
    parsedSerializedLiftedState.preloadedState
      ? (parse(parsedSerializedLiftedState.preloadedState) as S)
      : undefined;
  const nextLiftedState =
    'payload' in parsedSerializedLiftedState
      ? (parse(parsedSerializedLiftedState.payload) as LiftedState<
          S,
          A,
          unknown
        >)
      : parsedSerializedLiftedState;

  return { nextLiftedState, preloadedState };
}