unexpected-mobx
v1.0.0
Published
MobX plugin for the unexpected assertion library
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MobX plugin for unexpected.js
Assertions on effects triggered by actions
Let's start with a simple MobX store as example:
class Store {
@observable data = null;
@observable error = null;
@action.bound fetchData() {
// ...
}
@computed get loaded() {
return this.data || this.error;
}
}
export default new Store();
Now let's assert that after invoking fetchData
the data
property eventually gets set and error
remains null
:
import expect from 'unexpected';
import unexpectedMobX from 'unexpected-mobx';
expect.use(unexpectedMobX);
expect(store.fetchData,
'when observing',
() => store.loaded && store,
'to satisfy',
{
data: { foo: 42 },
error: null
}
)
The pattern looks like this:
<function> when observing <function> <assertion>
The first parameter is a function that invokes an action. If you use @action.bound
as in the example above, you can pass the store's action method directly.
The second parameter is a reactive function that is invoked via mobx.when. Once it returns a truthy value, this value will be passed on to the nested assertion.