Update a pull request branch

type Github = {

  token: string;

};

/**

 * Update a pull request branch

 * Updates the pull request branch with the latest upstream changes by merging HEAD from the base branch into the pull request branch.

 */

export async function main(

  auth: Github,

  owner: string,

  repo: string,

  pull_number: string,

  body: { expected_head_sha?: string; [k: string]: unknown }

) {

  const url = new URL(

    `https://api.github.com/repos/${owner}/${repo}/pulls/${pull_number}/update-branch`

  );

  const response = await fetch(url, {

    method: "PUT",

    headers: {

      "Content-Type": "application/json",

      Authorization: "Bearer " + auth.token,

    },

    body: JSON.stringify(body),

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`${response.status} ${text}`);

  }

  return await response.json();

}