JavaScript 5 ways to define a function

1. Function declaration

   JSX

   function sum(a, b) {
     return a + b;
   }

2. Function expression

   JSX

   const sum = function (a, b) {
     return a + b;
   };

   JSX

   const computer = {
     // Function expression
     sum: function (a, b) {
       return a + b;
     },
   };

3. Shorthand method definition

   JSX

   const computer = {
     // Shorthand method definition
     sum(a, b) {
       return a + b;
     },
   };

4. Arrow function

   JSX

   const sum = (a, b) => {
     return a + b;
   };

5. New function

   JSX

   const sum = new Function("a", "b", "return a + b");

My points

1. Don't use `New function` because it works like a `eval`.
2. Don't use shorthand method definition because it looks similar with arrow function.
3. To be consistent, use function expression on both function and method.
4. If you don't want the `this` of function itself, use arrow function.