Initializing React number input control with blank value?

Question

I'd like my controlled input to initialize with no value in the box. The input is a number, so I don't pass in an empty ''. Using defaultProps, I initialize the input with a null.

When typing into the input the console reports this message:

<MyInput> is changing an uncontrolled input of type number to be controlled. Input elements should not switch from uncontrolled to controlled (or vice versa).

To prevent this normally I initialize with an empty string to prevent this "switching" from happening. But with a number (I don't want to show a 0, I want nothing to show) I am not sure how to do it.

static defaultProps = {
    estimatedHours: null,
    estimatedMinutes: null,
  }

defalut values ^^

<input
   type="number"
   onChange={(e) => this.handleChange('Hours', e.target.value)}
   onKeyDown={this.handleKeyDown}
   onPaste={this.handlePaste}
   value={estimatedHours}
   placeholder={hoursText}
   className="slds-input th-trailmix-textbox th-time-component__input"
/>

Answer 1

Simpler approach is to have a fallback value be an empty string. Works for type=number as well.

<input type="number" value={estimatedHours || ''} />

Answer 2

You can set value Undefined,

Also add a check for input type if required

class Input extends React.Component {

    constructor(props) {
        super(props);
        this.state = {value: undefined};

        this.handleChange = this.handleChange.bind(this);
    }

    handleChange = (event) => {
        const isnum = /^\d+$/.test(event.target.value);
        if (isnum) {
            return this.setState({
                value: Number(event.target.value),
            });
        }
    };

    render() {
        return (
            <input
                type="number"
                onChange={this.handleChange}
                value={String(this.state.value)}
                placeholder={"Please enter number"}
            />
        );
    }
}

and convert String to Number and vice versa

This won't throw you an error for uncontrolled input