ReactJS autocomplete from React Bootstrap not working

I'm trying to build an autocomplete search field, using this form component from React Bootstrap, which is rendered as a input by the browser.

Here's what I did in my React component:

<FormControl
 id="frenchToEnglishInput"
 placeholder="type a word..."
 aria-label="Recipient's username"
 autocomplete="on"
 data={frenchToEnglishWords}
 onChange={this.fetchFrenchToEnglish}
 renderItem = {item => {
   return (
     <div>
       {item}
     </div>
   );
 }}
/>

the frenchToEnglishWords array is declared outside the component as a var, as I intend to update it as I type some value into the input field.

Now here is the function that triggers the onChange event :

fetchFrenchToEnglish = async () => {
    if(document.getElementById("frenchToEnglishInput").value!==''){

      axios.get(dictionaryURIs.english.French_English+""+document.getElementById("frenchToEnglishInput").value)
      .then(response => {
          frenchToEnglishWords = response.data
      })

    }
  }

The request is made from MongoDb, after setting up an autocomplete index on a collection, but this part works fine.

My question is, why is the only "autocomplete" I'm getting is the one made of the previous words I've typed ?

Or maybe the array I'm using as input data must be a const (as I've seen in many examples) and not a var ? When I do type in some word, I do not get any autosuggestion from the frenchToEnglishWords, which is being updated from the DB.