Day 1: Simple Types
Lesson 3: Variables
Constants are great but they are pretty inflexible, once you set it that's it forever.
Variables are the more flexible sibling to constants. You can create a variable, set it to a value and then later change that value to something new.
1let greeting = "hello"; 2console.log(greeting); 3 4greeting = "hello world"; 5console.log(greeting);
In the code above, we create a variable with the
let keyword called
greeting and set it to
hello. We then log it out, change it to
hello world and log it out again.
The first log will be
hello and the second
hello world. Note that when we change it to
hello world we don't use the
let keyword again. We only use let when we create the variable, if you were to put let in again you would get an error like: SyntaxError: Identifier 'greeting' has already been declared