Style
Since CSS-in-JS is all the rage right now, we'll recommend our official pick soon. In the meantime, for inline styles, there's the ReactDOM.Style.make API:
<div style=(
ReactDOM.Style.make(~color="#444444", ~fontSize="68px", ())
)/>
It's a labeled (typed!) function call that maps to the familiar style object {color: '#444444', fontSize: '68px'}. Note that make returns an opaque ReactDOM.style type that you can't read into. We also expose a ReactDOM.Style.combine that takes in two styles and combine them.
Escape Hatch: unsafeAddProp
The above Style.make API will safely type check every style field! However, we might have missed some more esoteric fields. If that's the case, the type system will tell you that the field you're trying to add doesn't exist. To remediate this, we're exposing a ReactDOM.Style.unsafeAddProp to dangerously add a field to a style:
let myStyle = ReactDOM.Style.make(~color="#444444", ~fontSize="68px", ());
let newStyle = ReactDOM.Style.unsafeAddProp(myStyle, "width", "10px");