Subscribe a device to a channel

//native

type Ably = {

  apiKey: string;

};

/**

 * Subscribe a device to a channel

 * Subscribe either a single device or all devices associated with a client ID to receive push notifications from messages sent to a channel.

 */

export async function main(

  auth: Ably,

  format: "json" | "jsonp" | "msgpack" | "html" | undefined,

  X_Ably_Version: string,

  body:

    | { channel?: string; deviceId?: string }

    | { channel?: string; clientId?: string },

) {

  const url = new URL(`https://rest.ably.io/push/channelSubscriptions`);

  for (const [k, v] of [["format", format]]) {

    if (v !== undefined && v !== "" && k !== undefined) {

      url.searchParams.append(k, v);

    }

  }

  const response = await fetch(url, {

    method: "POST",

    headers: {

      "X-Ably-Version": X_Ably_Version,

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

      Authorization: "Bearer " + auth.apiKey,

    },

    body: JSON.stringify(body),

  });

  if (!response.ok) {

    const text = await response.text();

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

  }

  return await response.json();

}