Function makeParamDecorator

packages/core/src/util/decorators.ts:103–147

(
  name: string,
  props?: (...args: any[]) => any,
  parentClass?: any,
)

}

export function makeParamDecorator(
  name: string,
  props?: (...args: any[]) => any,
  parentClass?: any,
): any {
  return noSideEffects(() => {
    const metaCtor = makeMetadataCtor(props);
    function ParamDecoratorFactory(
      this: unknown | typeof ParamDecoratorFactory,
      ...args: any[]
    ): any {
      if (this instanceof ParamDecoratorFactory) {
        metaCtor.apply(this, args);
        return this;
      }
      const annotationInstance = new (<any>ParamDecoratorFactory)(...args);

      (<any>ParamDecorator).annotation = annotationInstance;
      return ParamDecorator;

      function ParamDecorator(cls: any, unusedKey: any, index: number): any {
        // Use of Object.defineProperty is important since it creates non-enumerable property which
        // prevents the property is copied during subclassing.
        const parameters = cls.hasOwnProperty(PARAMETERS)
          ? (cls as any)[PARAMETERS]
          : Object.defineProperty(cls, PARAMETERS, {value: []})[PARAMETERS];

        // there might be gaps if some in between parameters do not have annotations.
        // we pad with nulls.
        while (parameters.length <= index) {
          parameters.push(null);
        }

        (parameters[index] = parameters[index] || []).push(annotationInstance);
        return cls;
      }
    }
    if (parentClass) {
      ParamDecoratorFactory.prototype = Object.create(parentClass.prototype);
    }
    ParamDecoratorFactory.prototype.ngMetadataName = name;
    (<any>ParamDecoratorFactory).annotationCls = ParamDecoratorFactory;
    return ParamDecoratorFactory;
  });
}

export function makePropDecorator(
  name: string,