You could use a higher order function to encapsulate the logic needed to run before a specific function is run. Higher order functions take functions as parameters, therefore a possible solution to your problem could look like this:

function withIsAdminUser(callback) {
  return function() { 
    if (isAdminUser()) {
      return false;
    }
    return callback();
  }
}

function getRaw() {
  // Do something here, this whole function could also be inlined
}
const get = withIsAdminUser(getRaw);

If you use TypeScript try decorators.

Docs: https://www.typescriptlang.org/docs/handbook/decorators.html#decorators

maybe you can define a function that can accept another function as an argument and returns false if that function (i.e isAdminUser in your code snippet) returns true

const checkUser = func => func() && false

then the function can be used like:

function update() {
    if (checkUser(isAdminUser)) {
        // update() logic will only run if user is not admin
    }

}
function get() {
   if (checkUser(isAdminUser)) {
      // get() logic will only run if user is not admin   
   }
 }