prototype

1/* Answer to: "javascript prototype explained" */
2
3/*
4  The prototype object is special type of enumerable object to
5  which additional properties can be attached to it which will be
6  shared across all the instances of it's constructor function.
7
8  So, use prototype property of a function in the above example
9  in order to have age properties across all the objects as
10  shown below:
11*/
12
13function Student() {
14    this.name = 'John';
15    this.gender = 'M';
16}
17
18Student.prototype.age = 15;
19
20var studObj1 = new Student();
21alert(studObj1.age); // 15
22
23var studObj2 = new Student();
24alert(studObj2.age); // 15

1String    Number.0.97.8.582..6985849
290.864.2.3.4.1..5785.9.6..77

1String.prototype.countCharacter = function(char) {
2    return [...this].filter(c => c === char).length;
3}