mutation.js

let mutation;

if (args) {
  const args1 = _.map(args, (type, name) => `$${name}: ${type}`); // e.g. $url: String
  const args2 = _.map(args, (type, name) => `${name}: $${name}`); // e.g. $url: url
  mutation = `
    mutation ${name}(${args1}) {
      ${name}(${args2})
    }
  `
} else {
  mutation = `
    mutation ${name} {
      ${name}
    }
  `
}