1var counter = (function() {  //exposed function references private state (the outer function’s scope / lexical environment) after outer returns. 
2 var privateCounter = 0;
3 function changeBy(val)   { privateCounter += val; }
4 return {  increment: function() {changeBy(1); },
5           decrement: function() {changeBy(-1);},
6           value: function() {return privateCounter; }
7  };
8})();
9
10counter.increment(); counter.increment();
11counter.decrement();
12counter.value();      //  1

1var counter = (function() {
2  var privateCounter = 0;
3  function changeBy(val) {
4    privateCounter += val;
5  }
6  return {
7    increment: function() {
8      changeBy(1);
9    },
10    decrement: function() {
11      changeBy(-1);
12    },
13    value: function() {
14      return privateCounter;
15    }
16  };
17})();
18
19console.log(counter.value()); // logs 0
20counter.increment();
21counter.increment();
22console.log(counter.value()); // logs 2
23counter.decrement();
24console.log(counter.value()); // logs 1
25

1func main() {
2  x := 0
3  increment := func() int {
4    x++
5    return x
6  }
7  fmt.Println(increment())
8  fmt.Println(increment())
9}

1function add(a) {
2     return function(b) {
3         return a + b;
4     };
5 }
6
7 let addTen = add(10);
8 let addSeven = addTen(7);
9
10 console.log(addSeven); // 17

1def say():
2    greeting = 'Hello'
3
4    def display():
5        print(greeting)
6
7    display()
8Code language: Python (python)