is-checks

This is just a POC and has NO real thoughts behind it.

This is basiaclly eventual-values with some extra methods that I wanted.

See:

• eventual-values

example

if ( isError(state) ) {
  return <Error message={ state } />
}
else if ( isPending(state) ) {
  return <Spinner />
}
else if ( isData(state) ) {
  return !isEmpty(state) ? state.map(item => <Item />) : <div>No items to display</div> : 
}

values

val	isOk(val)	isData(val)	isEmpty(val)	isPending(val)	isError(val)
undefined	false	false	true	true	false
null	true	false	true	false	false
1 (number)	true	true	false	false	false
'' (empty string)	true	true	true	false	false
'name' (string)	true	true	false	false	false
[] or {}	true	true	true	false	false
[1] or { value: true }	true	true	false	false	false
throw Error() or Promise.reject()	false	false	true	false	true