JSFiddle - React, Tailwind, and code Playground

by Thiago Figueiredo

JavaScript

var
    a,
    b,
    c,
    d,
    e;
// if you see in the console they all you show up as undefined
// because they exist but they have "no" value
console.log('a = ', a);
console.log('b = ', b);
console.log('c = ', c);
console.log('d = ', d);
// if you give them values
a = {
    name: 'Edwin',
    age: 17
};
b = [1, 2, 3];
c = 'What?';
d = function alertSomething(something) {
    console.log('it\'s time to alert!');
    alert(something);
};
// they will have values
// notice we did nothing with e
// it remains undefined
console.log('a = ', a);
console.log('b = ', b);
console.log('c = ', c);
console.log('d = ', d);
// we can use d as a function
// cause it is a function
d('let\'s alert something, people!');
// but if I try to use e as a function we'll have a problem
// because e is undefined and not a function...
console.log(e);
e('is it a function?', 42, true);