@moxy/redux-await-actions
v1.0.2
Published
Waits for specific actions to be dispatched or a timeout expires.
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redux-await-actions
Waits for specific actions to be dispatched or a timeout expires.
Installation
$ npm install @moxy/redux-await-actions --save-dev
Motivation
Consider the following example:
import thunkMiddleware from 'redux-thunk';
import { createStore, applyMiddleware, compose } from 'redux';
function login(username, password) {
return async (dispatch) => {
dispatch({ type: 'LOGIN_START', payload: { username, password } });
try {
const user = await fetch('/login', {
headers: { 'Content-Type': 'application/json' },
method: 'POST',
body: JSON.stringify({ username, password })
});
dispatch({ type: 'LOGIN_SUCCESS', payload: user });
} catch (err) {
dispatch({ type: 'LOGIN_FAIL', payload: err });
throw err;
}
// Side-effect: fetch orders asynchronously
// This action could be dispatched from a middleware as well. See below.
dispatch(fetchOrders());
}
}
const middlewares = [
thunkMiddleware,
// Middleware for real redux store. Mock store does not support middlewares.
({ dispatch, getState }) => (next) => (action) => {
const result = next(action);
if (action.type === 'LOGIN_SUCCESS') {
// Side-effect: fetch orders asynchronously
dispatch(fetchOrders());
}
return result;
}
];
const enhancer = compose(applyMiddleware(...middlewares));
const store = createStore(/* reducer */, /* initial state */, enhancer);
store.dispatch(login('username', 'password')).then(() => {
// For the sake of this example, assume Redux provides a getActions method
expect(store.getActions()).toContain([
'LOGIN_START',
'LOGIN_SUCCESS',
'FETCH_ORDERS_SUCCESS'
]);
});
The assertion above will fail because FETCH_ORDERS_SUCCESS
will not yet exist in the stack of actions. To solve this, one can use setTimeout
explicitly in each test:
store.dispatch(login('username', 'password'));
setTimeout(() => expect(store.getActions()).toContain([
'LOGIN_START',
'FETCH_ORDERS_SUCCESS'
]), 50);
However, this is not pretty and is error-prone. This library makes this easier for you. It works with both redux-mock-store and real redux store. It allows you to wait out for an arbitrary number of actions dispatched asynchronously as a result a side-effect by matching the actual contents of each dispatched action with the expected contents.
Usage
In order to ensure the store
passed to redux-await-actions
has a consistent interface when using either store (real and mock), a store enhancer is provided as an adapter to implement getActions
and clearActions
for the real store. The enhancer is exported as mockStoreAdapter
Check the examples below.
Example #1: action types
Supply the action types to wait for.
Real store
import awaitActions from '@moxy/redux-await-actions';
import configureStore from 'redux';
import thunkMiddleware from 'redux-thunk';
const middlewareEnhancer = compose(applyMiddleware(thunkMiddleware));
const composedEnhancers = compose(middlewareEnhancer, awaitActions.mockStoreAdapter);
const store = createStore(/* reducer */, /* initial state */, composedEnhancers);
store.dispatch(login('username', 'password'));
await waitForActions(store, ['LOGIN_START', 'FETCH_ORDERS_SUCCESS']);
Mock store
import awaitActions from '@moxy/redux-await-actions';
import configureStore from 'redux-mock-store';
import thunkMiddleware from 'redux-thunk';
const store = configureStore([thunkMiddleware])();
store.dispatch(login('username', 'password'));
await waitForActions(store, ['LOGIN_START', 'FETCH_ORDERS_SUCCESS']);
Example #2: action objects
Supply the action objects to wait for, matching a subset of the properties of the dispatched actions. It performs a deep comparison between property values of dispatched and expected actions to determine whether the expected actions are partially contained in the stack of dispatched actions.
Mock store
import awaitActions from '@moxy/redux-await-actions';
import configureStore from 'redux-mock-store';
import thunkMiddleware from 'redux-thunk';
const store = configureStore([thunkMiddleware])();
store.dispatch(login('username', 'password'));
// { type: 'LOGIN_START', payload: { username: 'username' } }
// matches
// { type: 'LOGIN_START', payload: { username: 'username', password } }
//
// { type: 'FETCH_ORDERS_SUCCESS' }
// matches
// { type: 'FETCH_ORDERS_SUCCESS', payload: orders }
await waitForActions(store, [
{
type: 'LOGIN_START',
payload: { username: 'username' },
},
{
type: 'FETCH_ORDERS_SUCCESS',
},
]);
Real store
import configureStore from 'redux';
import thunkMiddleware from 'redux-thunk';
const middlewareEnhancer = compose(applyMiddleware(thunkMiddleware));
const composedEnhancers = compose(middlewareEnhancer, awaitActions.mockStoreAdapter);
const store = createStore(/* reducer */, /* initial state */, composedEnhancers);
store.dispatch(login('username', 'password'));
// { type: 'LOGIN_START', payload: { username: 'username' } }
// matches
// { type: 'LOGIN_START', payload: { username: 'username', password } }
//
// { type: 'FETCH_ORDERS_SUCCESS' }
// matches
// { type: 'FETCH_ORDERS_SUCCESS', payload: orders }
await waitForActions(store, [
{
type: 'LOGIN_START',
payload: { username: 'username' },
},
{
type: 'FETCH_ORDERS_SUCCESS',
},
]);
API
awaitActions(store, actions, [options])
Returns a Promise
which fulfills if all actions
are dispatched before the timeout expires. The Promise
has a .cancel()
function which, if called, will reject the Promise
.
The Promise
might be rejected:
- as a result of timeout expiration, throwing
TimeoutError
- as a result of
.cancel()
invocation, throwingCancelledError
- when the action's matcher throws
MismatchError
NOTE: Subsequent calls to awaitActions
with the same actions should be preceded by a call to store.clearActions()
, otherwise the returned Promise
will resolve immediately.
store
Type: Object
The redux-mock-store
or redux
store enhanced with awaitActions.mockStoreAdapter
.
actions
Type: Object | String | Array | Function
The actions to wait for. It can be either:
String
: an action type string.Object
: an action object.Array
of either- action objects;
- action type strings;
- action objects mixed with action type strings.
options
timeout
Type: Number
Default: 2000
The timeout given in milliseconds.
throttleWait
Type: Number
Default: 0
Specifies the time in milliseconds that every invocation to the action's matcher take place at since the last invocation. When set to zero, throttling is disabled.
When throttling is enabled, the matcher
will be called at most once per throttleWait
milliseconds receiving the array of actions dispatched until that time. If the matcher
does not resolve the Promise
until timeout
milliseconds have elapsed, the Promise
is rejected throwing TimeoutError
.
This feature is useful when one needs to wait for several actions or a burst of actions to be dispatched, effectively skip invocations to the action's matcher until the Redux store "settles" to avoid running complex action comparison logic in the meantime and improve performance.
matcher
Type: Function
Default: awaitActions.dispatchOrderMatcher
Supplies custom behavior to specify how expected and dispatched actions should be compared. The function accepts two arguments: the array of expected actions and dispatched actions.
The matcher must either:
- return
true
to indicate a match has occurred and fulfill thePromise
. - return
false
to indicate a match is yet to occur and thePromise
remains in pending state. - throw
MismatchError
to indicate a match will not occur anymore and reject thePromise
.
Two built-in matchers are already shipped:
dispatchOrderMatcher
performs a comparison between the specified order of expected actions against the order of arrival of dispatched actions. On the first mismatch detected,MismatchError
is thrown for early rejection.wasDispatchedMatcher
matcher is a less strict matcher which checks whether expected actions are contained within dispatched actions.
Both matchers perform a partial deep comparison between dispatched and expected actions, as per Lodash's isMatch().
Example of a custom matcher implementation:
import awaitActions from '@moxy/redux-await-actions';
import configureStore from 'redux-mock-store';
import thunkMiddleware from 'redux-thunk';
const store = configureStore([thunkMiddleware])();
const expectedActions = [
{ type: 'LOGIN_START', payload: { username: 'username' } },
{ type: 'FETCH_ORDERS_SUCCESS' }
];
store.dispatch(login('username', 'password'));
// Throws if LOGIN_FAIL is dispatched or
// Matches when LOGIN_START and FETCH_ORDERS_SUCCESS are dispatched
awaitActions(store, expectedActions, { matcher: (expectedActions, storeActions) => {
const hasLoginFail = storeActions.some((action) => action.type === 'LOGIN_FAIL');
if (hasLoginFail) {
throw new waitForActions.MismatchError();
}
const hasLoginStart = storeActions.some((action) => action.type === 'LOGIN_START' && action.payload.username === 'username');
const hasFetchOrdersSuccess = storeActions.some((action) => action.type === 'FETCH_ORDERS_SUCCESS');
return hasLoginStart && hasFetchOrdersSuccess;
}})
.then(() => {
// Expected actions were dispatched
})
.catch((err) => {
// MismatchError
});
Tests
$ npm test
$ npm test -- --watch
during development