Else-if and Nesting

There may be cases where you want to execute different code blocks depending on multiple conditions. In this case, you can use an else if statement.

Let's make this a bit more interesting and have certain logs during certain hours.

const d = new Date();
const hour = d.getHours();

if (hour < 12) {
  console.log('Good Morning!');
} else if (hour < 18) {
  console.log('Good Afternoon!');
} else {
  console.log('Good Night!');
}

Nesting

There may be cases where you need to have if statements inside of if statements. In this case, you can use a nested if statement.

if (hour < 12) {
  console.log('Good Morning!');

  if (hour === 6) {
    console.log('Wake up!');
  }
} else if (hour < 18) {
  console.log('Good Afternoon!');
} else {
  console.log('Good Night!');

  if (hour >= 20) {
    console.log('zzzzzzzzzzz!');
  }
}

Multiple conditions

We can test for multiple conditions in the same if statement by using the && (AND) and the || (OR) logical operators.

if (hour >= 7 && hour < 15) {
  console.log('It is work time!');
}

if (hour === 6 || hour === 20) {
  console.log('Brush your teeth!');
}