call two functions within onchange event in react

You can only assign a handler to onChange once. When you use multiple assignments like that, the second one will overwrite the first one.

You will either have to make a handler that calls both functions, or use an anonymous function:

twoCalls = e => {
  this.functionOne(e)
  this.functionTwo()
}
.
.
.
<FormControl
    name="searching"
    placeholder="Searching"
    onChange={this.twoCalls}
/>

Or...

<FormControl
    name="searching"
    placeholder="Searching"
    onChange={e => { this.functionOne(e); this.functionTwo() }}
/>

if you need props you can use it

<FormControl
    name="searching"
    placeholder="Searching"
    onChange={e => { this.functionOne(e); this.props.functionTwo(e)}
/>