I am learning javascript and Angular, Because at the moment of seeing the data type of this variable even specifying the data type it still comes out as string being a number
this.activatedRoute.params.subscribe( params => {
const idx: number = (<number>params['id']);
console.log('por que string??? ' + typeof idx);
this.category = this._categoryService.getCategory( idx );
});
Try using the parseInt() method to convert from string to number :
const idx: number = parseInt(params['id']);
console.log('por que string??? ' + typeof idx);
this.category = this._categoryService.getCategory( idx );
A <Type> is called Type Assertation . According to the documentation:
Type assertions are a way of telling the compiler "believe me, I know what I'm doing. "A type assertion is like a type of conversion in other languages, but does not perform any verification special or data restructuring. It has no impact on time of execution, and the compiler uses it exclusively. TypeScript assumes that you, the programmer, have made the special controls that you need
Which means that you do not necessarily cast it, but only provide more information about the type to cast.