Simple if branch

here a statement is executed based on condition

if (true) {
console.log('entered') // prints 'entered' as condition is true
}

if..else branch

here either statement is executed based on condition

if (0>1) {
console.log('greater than one')
} else {
console.log('less than one') // prints 'less than one' as condition is not satisfied
}

if..else if..else branch

here one of the statement block is executed based on condition. we can chain multiple condition by using 'else if'

var i = 0;
if (i > 1) {
console.log('greater than one')
} else if (i == 0) {
console.log('value is zero') // prints 'value is zero' as condition is not satisfied
} else {
console.log('less than one')
}

switch branch

this is similar to else..if chain. I the condition is based on single value then switch can be used.

In switch, The interpreter checks each case against the value of the expression until a match is found. If nothing matches, a default condition will be used. This match uses strict check i.e ===. break plays a very important role in switch.

var grade = 'A';
switch (grade) {
case 'A':
console.log('great job')
break
case 'B':
console.log('well done')
break
default:
console.log('Unknown grade')
} // prints 'great job'