Authentication state machine

auth_state_machine.js

const TIMEOUT_MS = 2000;

const FSM_DEF = {
  id: 'tokenRequest',
  initial: 'timing',
  context: {
    payload: { statusCode: 500, body: '{"error":"Unknown error [init]"}'},
  },
  states: {
    timing: {
      initial: 'authenticating',
      after: {
        [TIMEOUT_MS]: 'resolve',
      },
      states: {
        authenticating: {
          invoke: {
            id: 'authenticate',
            src: ctx => cb => {
              ctx.authenticate()
                .then(auth => cb(auth ? 'AUTHORIZED' : 'UNAUTHORIZED'))
                .catch(() => cb('ERROR'));
            },
            onError: { actions: send('ERROR') },
          },
          on: {
            UNAUTHORIZED: { actions: 'setUnauthorized' },
            AUTHORIZED: {
              actions: 'setAuthorized',
              target: 'done',
            },
            ERROR: { actions: 'setError' },
          },
        },
        done: { type: 'final' },
      },
      onDone: 'resolve',
    },
    resolve: {
      type: 'final',
    },
  },
};
const FSM_OPTS = {
  actions: {
    setTryAgain: assign({
      payload: ctx => ({
        statusCode: 503,
        body: '{"error":"Try again later"}',
      }),
    }),
    setUnauthorized: assign({
      payload: ctx => ({
        statusCode: 401,
        body: JSON.stringify(ctx.getUnauthorizedDetail(ctx.event)),
      }),
    }),
    setAuthorized: assign({
      payload: ctx => ({
        statusCode: 201,
        body: JSON.stringify(ctx.getPayload()),
      }),
    }),
    setError: assign({
      payload: ctx => ({
        statusCode: 500,
        body: '{"error":"Unknown error"}',
      }),
    }),
  },
};