JavaScript is a "dynamically typed language", which means that, unlike some other languages, you don't need to specify what data type a variable will contain (numbers, strings, arrays, etc).
For example, if you declare a variable and give it a value enclosed in quotes, the browser treats the variable as a string:
let myString = 'Hello'; // You may use double quotes ("") or single quotes ('') for a string
Even if the value contains numbers, it is still a string, so be careful:
let myNumber = '500'; // oops, this is still a string
typeof myNumber;
myNumber = 500; // much better — now this is a number
typeof myNumber;
Try to play with the four lines above, in BR Lab / code editor one by one, and see what the
results are.
You'll
notice that we are using a special operator called typeof — this returns the data type of the
variable you
type after it. The first time it is called, it should return string, as at that point the myNumber
variable contains a string, '500'. Have a look and see what it returns the second time you call it.
