Getting some trouble to do the following in typescript. I've the following interface defined :
interface RendererCallback {
getNode():HTMLElement;
getTable();
}
There is a method expecting a RenderCallback object like :
render( callback:RendererCallback )
How do I create an anonymous instance in the middle of my code :
myObject.render( new .. {
getNode() {
return myNode;
}
getTable() {
.. some code...
return something;
}
} );
You can use anonymous objects and lambdas:
myObject.render({
getNode: () => { doSomething...; return myNode },
getTable: () => myTable
});
Note, the new keyword is not used.
return statement is implicit for single-expression lambdas without brackets. It's equivalent to this in vanilla JavaScript: getNode: function() { return myNode; }Typescript now supports class expressions so you can make actual anonymous classes.
myObject.render( new class {
getNode() {
return myNode;
}
getTable() {
.. some code...
return something;
}
} );
This has the benefit of this not being inferred to be any within the anonymous class' methods.
new class implements MyInterface or new class extends MyClass { } (constructorArgs)Here's a full code sample that works:
interface RendererCallback {
getNode():HTMLElement;
getTable();
}
class thing {
render(callback: RendererCallback) {
}
}
var myObject = new thing();
myObject.render( {
getNode() {
return null;
},
getTable() {
}
}
);
I find it to nice to declare it like this:
propertyName: RendererCallback = {
getNode: () => myNode, // no braces needed to only return something
getTable() => {
.. some code...
return something;
}
};
