2b 3d js

1addition assignment operator

1Addition assignment (+=) The operator ( += ) 
2adds the value of the right operand to a variable

1Operator

1/* JavaScript shorthand -=
2-= is shorthand to subtract something from a
3variable and store the result as that same variable.
4*/
5
6// The standard syntax:
7var myVar = 5; 
8console.log(myVar) // 5
9var myVar = myVar - 3;
10console.log(myVar) // 2
11
12// The shorthand:
13var myVar = 5;
14console.log(myVar) // 5
15var myVar -= 3;
16console.log(myVar) // 2
17

1 (req, res, next) = () => 
2