Dynamic page title with ReactJS

I want to make a Dynamic page title on ReactJS. I try a lot of things , but didn't succeed. I make an array with data:

let pageTitles = [
    {key:"/Home", title:"Welcome Home"},
    {key:"/SecondPage", title:"Shop"},
    {key:"/ThirdPage", title:"ContactUs"},
];

In html is only <title></title> , I use let pathname = window.location.pathname; If it return "/Home" or "/ThirdPage" to set a new title dynamically. I've tried something like that:

for (var i = 0, len = pageTitles.length; i < len; i++) {
        if (pageTitles[i].key === pathname) {
            var hhh = pageTitles[i].text;
        }
    }
document.title = hhh

But obviously didn't work. I'm sorry if there is a topic like that, but I didn't found it.I have a restriction to install modules.

If you need to avoid installing modules, you could do this as helper file, then just import it in module you need and call in componentDidMount

export function seo(data = {}) {
  data.title = data.title || 'Default title';
  data.metaDescription = data.metaDescription || 'Default description';

  document.title = data.title;
  document.querySelector('meta[name="description"]').setAttribute('content', data.metaDescription);
}

import React from 'react';
import {seo} from '../helpers/seo';

export default class SomeClass extends Component {
  constructor(props) {
    super(props);
  };

  componentDidMount() {
    seo({
      title: 'This is my title only shown on this page',
      metaDescription: 'With some meta description'
    });
  }

  render() {
    return <h1>Hello World</h1>;
  }
}

You could also just call directly document.title = 'My new title' anywhere, but if you extract it as function you have the option to have default one and just provide override when you want to.

Edit: upon inspecting your code, if you change hhh = pageTitles[i].text; to hhh = pageTitles[i].title; it will work. Would be nice to declare the var outside of the loop. Also would be nice to have default value.