Function setClassMetadata

packages/core/src/render3/metadata.ts:87–121

(
  type: any,
  decorators: any[] | null,
  ctorParameters: (() => any[]) | null,
  propDecorators: {[field: string]: any} | null,
)

 * being tree-shaken away during production builds.
 */
export function setClassMetadata(
  type: any,
  decorators: any[] | null,
  ctorParameters: (() => any[]) | null,
  propDecorators: {[field: string]: any} | null,
): void {
  return noSideEffects(() => {
    const clazz = type as TypeWithMetadata;

    if (decorators !== null) {
      if (clazz.hasOwnProperty('decorators') && clazz.decorators !== undefined) {
        clazz.decorators.push(...decorators);
      } else {
        clazz.decorators = decorators;
      }
    }
    if (ctorParameters !== null) {
      // Rather than merging, clobber the existing parameters. If other projects exist which
      // use tsickle-style annotations and reflect over them in the same way, this could
      // cause issues, but that is vanishingly unlikely.
      clazz.ctorParameters = ctorParameters;
    }
    if (propDecorators !== null) {
      // The property decorator objects are merged as it is possible different fields have
      // different decorator types. Decorators on individual fields are not merged, as it's
      // also incredibly unlikely that a field will be decorated both with an Angular
      // decorator and a non-Angular decorator that's also been downleveled.
      if (clazz.hasOwnProperty('propDecorators') && clazz.propDecorators !== undefined) {
        clazz.propDecorators = {...clazz.propDecorators, ...propDecorators};
      } else {
        clazz.propDecorators = propDecorators;
      }
    }
  }) as never;
}