Okay, I looked at the TypeScript definition file and there are typings missing, we'll look into that. Here's one example of a temporary workaround:
graphic: new Graphic ({
geometry : {
type : 'point' , // autocasts as new Point()
longitude : - 71.2643 ,
latitude : 42.0909
} as __esri.Point,
symbol : {
// @ts-ignore
type : 'simple-line',
size : '12px' ,
color : 'blue' ,
outline : {
color : '#efefef' ,
width : '1.5px'
}
}});
[Edit: just a footnote, my suggestions are based on 4.18/4.19-next]