Functions have two places where types are applied: parameters (input) and the return value (output).| flow.org
Learn how to enable stricter type checking on a file-by-file basis.| flow.org
Warning: Do not mistake any with mixed. It's also not the same as empty.| flow.org
Objects can be used in many different ways in JavaScript.| flow.org
Refinements allow us to narrow the type of a value based on conditional tests.| flow.org