jeremiah-stanley-turing-ta-interview-conditionals.md

Conditionals

Conditional let us determine when we do what

Using conditionals allows us to protect code from executing until the proper conditions are met.

Think of conditionals a way of putting a wall around a walled city. Your city has a gate, but you hold the power to open that gate from the right people.

Let's look at an example:

var age = 18

if (age < 21) {
  console.log('Sorry kid, I can't serve you')
}

In this example, we are comparing two numbers, if age is less than (<) 21 we execute the console.log within the brackets. In the age the expression age < 21 evaluates to true, so we execute the console.log. This brings us to our next concept.

Truthy and Falsy Values

In javascript we a boolean data types that are explicitly true or false, but javascript assigns everything a truthy or falsy value. In if blocks and ternaries we can use truthy and falsy values as conditions

Let's go over some common truthy and falsy values in javascript.

Truthy Values

• [] - empty arrays
• {} - empty objects

Falsy Values

• '' - empty strings
• null
• undefined
• 0
• NaN

Boolean Coercion