@universis/candidates/src/utils/insertListener.js

Universis api server plugin for study program candidates, internship selection etc

import { Args } from '@themost/common';

/**
 *
 * @param {*} listener Object {type: string}
 * @param {*} model model definition (via DataConfiguration or SchemaLoader strategies)
 * @returns true if the listener was inserted (model definition has to be updated outside of this function), false otherwise
 */
export function insertListener(listener, model) {
  Args.check(listener && typeof listener.type === 'string' && model);
  // ensure model event listeners
  model.eventListeners = model.eventListeners || [];
  // try to find target listener
  const listenerExists = model.eventListeners.find((eventListener) => {
    return (
      eventListener.type === listener.type ||
      eventListener.type === listener.type.replace(/\.js$/, '')
    );
  });
  // if it exists, exit
  if (listenerExists) {
    return false;
  }
  // check insertBefore
  if (typeof listener.insertBefore !== 'string') {
    // push the listener and exit
    model.eventListeners.push({
      type: listener.type
    });
    return true;
  }
  // find before listener's index
  const beforeListener = model.eventListeners.findIndex((eventListener) => {
    return (
      eventListener.type.endsWith(listener.insertBefore) ||
      eventListener.type.endsWith(listener.insertBefore.replace(/\.js$/, ''))
    );
  });
  // if it's not there
  if (beforeListener < 0) {
    // push the listener and exit
    model.eventListeners.push({
      type: listener.type
    });
    return true;
  }
  // push the listener at the specified index
  model.eventListeners.splice(beforeListener, 0, {
    type: listener.type
  });
  return true;
}