Why the filter method is not working when filtering an array of objects requested from an API (Javascript)

I have been practicing some coding after some break. I’m trying to filter an array of objects from an api and creating a function the which will return me every word from the title of the fetch I’m making the request.

However, when I want to do the filter it shows that filter method is not recognized, and I don’t know if its affected if you are filtering an array that you called from an api.

This is the code.

function titles(word){
    let sentence
    let array = []
    let api = 'https://jsonplaceholder.typicode.com/posts'
    let data = fetch(api)
    let response = data.then(res => res.json()).then(data => data.map((e) => { e.title}))
    array = array.concat(response)
    sentence = Promise.all(array.flat()).then(results => results.flat())
  const people = sentence.filter(e => e.title.includes(word))
    return people

However, returns an error message (see image)

But when I do the same on an array of objects the filter works well.

I appreciate any help, feedback and code improvement. Thanks in advance!

error message