Skip to content

Latest commit

 

History

History
32 lines (21 loc) · 926 Bytes

bs.val.md

File metadata and controls

32 lines (21 loc) · 926 Bytes
Raw

[@bs.val]

bs.val allows you to access JS values that are available on the global scope.

For example:

[@bs.val] external setTimeout: (unit => unit, int) => int = "setTimeout";

setTimeout(() => Js.log("Hello"), 1000);

Tip: When BS and JS names match, you can use a "" shorthand:

[@bs.val] external setTimeout : (unit => unit, int) => int = "";
[@bs.val] external clearTimeout: int => unit = "";

Let's make sure that clearTimeout can only get timeoutIDs returned by setTimeout, not any int.

Abstract types to the rescue!

type timeoutID;
[@bs.val] external setTimeout: (unit => unit, int) => timeoutID = "";
[@bs.val] external clearTimeout: timeoutID => unit = "";

What if the value we want to access is on another global object, e.g. Math.floor, Date.now, or even location.origin.length?

That's what bs.scope is for. Check it out!