Setting, deleting and retrieving cookies in Typescript.

cookie-typescript-utils.ts

 /*
 * General utils for managing cookies in Typescript.
 */
  private setCookie(name: string, val: string) {
    const date = new Date();
    const value = val;

    // Set it expire in 7 days
    date.setTime(date.getTime() + (7 * 24 * 60 * 60 * 1000));

    // Set it
    document.cookie = `${name}=${value};expires=${date.toUTCString()};path=/`;
  }

  private getCookie(name: string) {
    const value = `; ${document.cookie}`;
    const parts = value.split(`; ${name}=`);

    if (parts.length === 2) {
      return parts.pop().split(';').shift();
    }
  }

  private deleteCookie(name: string) {
    const date = new Date();

    // Set it expire in -1 days
    date.setTime(date.getTime() + (-1 * 24 * 60 * 60 * 1000));

    // Set it
    document.cookie = `${name}=;expires=${date.toUTCString()};path=/`;
  }

Try adding a return after the if block to cover that case.
if (parts.length === 2) {
...return the good stuff....
}
return undefined; // or null or empty string or whatever you think is appropriate