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')
case 'B':
console.log('well done')
console.log('Unknown grade')
} // prints 'great job'