terriajs/lib/Core/superGet.ts

Geospatial data visualization platform.

import DeveloperError from "terriajs-cesium/Source/Core/DeveloperError";

/**
 * Gets the value of a named property from a superclass of an instance. If the superclass has
 * MobX decorators, they are ignored, and the property value is retrieved directly.
 * @param source The first class to search for the named property.
 * @param propertyName The name of the property to get.
 * @param instance The instance for which to get the property value.
 */
export default function superGet(
  source: any,
  propertyName: any,
  instance: any
): any {
  while (source !== undefined) {
    let propertyDescriptor;
    if (
      source.__mobxDecorators !== undefined &&
      source.__mobxDecorators[propertyName] !== undefined
    ) {
      propertyDescriptor = source.__mobxDecorators[propertyName].descriptor;
    }

    if (propertyDescriptor === undefined) {
      propertyDescriptor = Object.getOwnPropertyDescriptor(
        source,
        propertyName
      );
    }

    if (propertyDescriptor !== undefined) {
      if (propertyDescriptor.get !== undefined) {
        return propertyDescriptor.get.call(instance);
      } else {
        return propertyDescriptor.value;
      }
    }

    source = Object.getPrototypeOf(source);
  }

  throw new DeveloperError(
    "A property named " + propertyName + " was not found in any superclass."
  );
}