If you take a look at the documentation, it uses a string: https://reactjs.org/docs/dom-elements.html#all-supported-html-attributes
<div tabIndex="-1" /> // Just like node.tabIndex DOM API
But the types state that it should be a number:
https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/react/v16/index.d.ts#L1767
tabIndex?: number;
If you take a look at the documentation, it uses a string: https://reactjs.org/docs/dom-elements.html#all-supported-html-attributes
<div tabIndex="-1" /> // Just like node.tabIndex DOM APIBut the types state that it should be a number:
https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/react/v16/index.d.ts#L1767
tabIndex?: number;