graphql.js

// query is a GraphQL query definition and variables an object whose keys are variable values for that definition
fetch(
    "/graphql",
    {
        method: "POST",
        credentials: "same-origin",
        headers: {
            "Content-Type": "application/json"
        },
        body: JSON.stringify({
            query,
            variables
        })
    }
)
.then(response => response.json())
.then(({ data, errors}) => ... )