JavaScript 5 ways to define a function

1. Function declaration

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

2. Function expression

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

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

3. Shorthand method definition

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

4. Arrow function

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

5. New function

    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.