Promises and garbage collection - ecmascript-6

Question

I have setup a project with react-redux and I use redux-thunk in my action-creators to do fetching. Here is an example of my thunk:
export const doPostRequest = id => {
return (dispatch, getState) => {
const { id : initiailId } = getState().currentSelection
return api.post(id).then(response => {
if (!isEqual(initialId, getState().currentSelection.id)){
return;
}
dispatch(someOtherAction(id))
return Promise.resolve(true)
})
.catch(err => {})
}
}
As you can see i want to escape the doPostRequest if the currentSelection of my state is changed by the time the response is receieved. Otherwise I return Promise.resolve(true) so the onSubmit in MyComponent can reset the form:
Inside a component (which is a form) i have the following for onSubmit:
class MyComponent extends React.PureComponent{
onSubmit = id => {
this.props.dispatch(doPostRequest(id))
.then(shouldReset => shouldReset && resetForm())
}
render(){
return <form onSubmit={this.onSubmit}>.....</form>
}
}
In most cases, when I really dont have to do anything else except fetching values, I dont do a Promise-chain on the thunk, even though it returns a promise, but here I need to do a resetForm once the postrequest is a success.
Is this implementation good enough, also when it comes to GC ? How are Promises garbage collected ? Is there a problem if I return a fetch().then() without chaining it further?