Intrinsic elements

Intrinsic elements

Intrinsic elements are looked up on the special interface JSX.IntrinsicElements. By default, if this interface is not specified, then anything goes and intrinsic elements will not be type checked. However, if interface is present, then the name of the intrinsic element is looked up as a property on the JSX.IntrinsicElements interface. For example:

declare namespace JSX {
  interface IntrinsicElements {
    foo: any
  }
}

<foo />; // ok
<bar />; // error

In the above example, <foo /> will work fine but <bar /> will result in an error since it has not been specified on JSX.IntrinsicElements.

Note: You can also specify a catch-all string indexer on JSX.IntrinsicElements as follows: ts declare namespace JSX { interface IntrinsicElements { [elemName: string]: any; } }