I am reading a Javascript book: Good Details. I am a little confused when I read the code below:
Function.prototype.method = function (name, func) { this.prototype[name] = func; return this; }; Number.method('integer',function(){ return Math[this < 0 ? 'ceil' : 'floor'](this); });
I think the first part of the above code means that any JavaScript function now has a method called a method. But is the "number" also a function? Why Number.method meaning of Number.method make sense?
I assume that Number inherits from Number.prototype, which inherits from Object.prototype (Number-> Number.prototype-> Object.prototype), since Number does not have a “method” method at the beginning, it will search for it by prototype chain. But Function.prototype is not in the chain, right?
What is the relationship between Number, Number.prototype and Function.prototype?
UPDATE I:
I was looking for more information and now more confused. Some say Number is actually a function, and this seems to make sense because the value of Number instanceof Function is true . But the value (-10 / 3) instanceof Number is false . Doesn't that bother you? If the number in mathematics (for example, 3, 2.5, (-10/3)) is not even Number in JavaScript, how (-10 / 3) call integer() , which is a method from Number ? (The line below is in the same book)
document.writeln((-10 / 3).integer());
UPDATE II:
The problem is solved, basically.
Thanks to @Xophmeister help, I have now come to the conclusion that Number can call method because Number is a constructor, so it is associated with Function.prototype . As to why the number (3, 2.5, (-10/3)), whose type is a primitive type in JavaScript, can call a method that has a Number object, you should refer to this page .
I got this conclusion mainly from @Xophmeister help and a little search so that it is not accurate enough. Any corrections or additions are welcome.