fix: no optional for strict js usage

src/linq/enumerable.ts

@@ -71,7 +71,7 @@ export class Enumerable<TEntity extends Entity> extends Base<TEntity> {
  * @param predicate javascript expression
  * @param parameters any javascript parameters has to be declared
  */
- public where(predicate: (it: TEntity, ...param: any[]) => boolean, ...param: any[]): this
+ public where(predicate: (it: Required<TEntity>, ...param: any[]) => boolean, ...param: any[]): this
  public where(predicate: any, ...param: any[]): this {
  this.operators.push(<LinqOperator<TEntity>>whereOperator(predicate, ...param))