An example of using fetch for graphql endpoints

fetch-graphql.js

fetch('/graphql', {
    method: 'POST',
    credentials: 'same-origin',
    headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${storefrontToken}`
    },
    body: JSON.stringify({
      query: gqlQueryString
    })
  })
  .then(response => response.json())
  .then(result => console.log(result))
  .catch(error => console.error(error));