How to trigger focus on an input field and force the keyboard to be invoked in React?

Question

JavaScript

There is an input component. The react-input-mask is screwed to it. It is necessary that when the page loads, the input field has focus and the keyboard is shown (in this case, a numeric one).
I set the ref to the component inside the component itself (I found the option for focus with findDOMNode, the usual ref does not work - this.inputRef returns null)

<InputMask
     ref={ref => this.inputRef = findDOMNode(ref)}
/>

I hang on ComponentDidMount of the component

componentDidMount() {
      this.inputRef.focus();
  }

And it works on desktop. And the phone is somehow strange. When you go to the page - there is no focus. But if you poke in the field and reload the page, the focus remains. But the keyboard is not shown anyway.