Only numbers. Input number in React

I tried to mimic your code and noticed that there's an issue on React with <input type='number' />. For workaround, check this example and try it yourself: https://codepen.io/zvona/pen/WjpKJX?editors=0010

You need to define it as normal input (type='text') with pattern for numbers only:

    <input type="text" pattern="[0-9]*"
     onInput={this.handleChange.bind(this)} value={this.state.financialGoal} />

And then to compare the validity of input:

const financialGoal = (evt.target.validity.valid) ? 
  evt.target.value : this.state.financialGoal;

The biggest caveat on this approach is when it comes to mobile --> where keyboard isn't in numeric but in normal alphabetic format.

Simply way in React

<input
      onKeyPress={(event) => {
        if (!/[0-9]/.test(event.key)) {
          event.preventDefault();
        }
      }}
    />