JavaScript language core-the Next Day

valueof () and ToString () in JavaScript

[1] The ToString () method converts a logical value to a string and returns the result.

[2] ValueOf () returns the original value of the specified object.

var m = [' 1 ', ' 2 ', ' 3 '];

M.valueof (); return [' 1 ', ' 2 ', ' 3 ']

M.tostring (); Back to

The toString () and valueof () methods are object objects, and since all objects inherit the object instance, almost all instance objects are available, except for null.

Common and different points of the two

The ToString () method and the ValueOf () method are called automatically when the object is output.

The ToString method is called first when a string type conversion is performed, and the ValueOf method is called first when a numeric conversion is performed.

var s = {
I:10,
Valueof:function () {return this.i+30;},
Tostring:function () {return this.valueof () +10;}
} 

Alert (S > 20); Returns True
alert (+s); Returns 40
alert (s); Returns 50

Summary: valueof is biased towards arithmetic, and ToString is biased towards display.

JavaScript language core-the Next Day