JS Array Function

Another way to create a function and assign it to a variable (this process is called #Function Expression) is called arrow function, which is similar to Python Lambda Function

let myFun = (para1, para2) => expression

This creates a function myFun that accepts arguments para1 and para2, then evaluates the expression on the right side with their use and returns its result.

In other words, it’s the shorter version of the #Function Expression:

let myFun = function(para1, para2) {
  return expression;
};

• If we have only one parameter, then parentheses around parameters can be omitted
  • This gives the simplest form of a function: para => expression
• If there are no parameters, parentheses will be empty (but they should be present)
• For more complex expressions, like multiple expressions or statements, we should enclose them in curly braces {}, then use a normal return within them

let age = prompt("What is your age?", 18);

let welcome = (age < 18) ?
  () => alert('Hello') :
  () => alert("Greetings!");

welcome();

by zcysxy