Loops

Loops are used to create loop in your code. JavaScript provides 3 types of loops and they are

For

One of most used loops of all time.

// for(declaration; condition; increment)
for(let i=0; i<7; i++) {
  console.log("i = ", i)
}

Let's understand it's syntax.

for: This is the keyword (reserved word) used to define.
let i=0 or declaration: These can further be divided in 2 types
i<7 or condition: This is the keyword (reserved word) used to define.
i++ or increment: These represent the body of the if and else. when the condition is true, code withing if block will get execute or the code with within else block will get executed.

// Is it a valid loops
for(let i=0; i<7;) {
  console.log("i = ", i)
}
// Don't run it.

The while keyword can be used to run a loop while a condition is true.

let i=0;
while(i<7) {
  console.log("i = ", i)
  i++;
}

Let's understand it's syntax.

while: This is the keyword (reserved word) used to define.
let i=0 or declaration: These can further be divided in 2 types
i<7 or condition: This is the keyword (reserved word) used to define.
i++ or increment: These represent the body of the if and else. when the condition is true, code withing if block will get execute or the code with within else block will get executed.

The do keyword is used to start the body of the loop and while keyword is used at the end to declare the condition.

let i=0;
do {
  console.log("i = ", i)
  i++;
}while(i<7);

Let's understand it's syntax.

do: This is the keyword (reserved word) used to define.
let i=0 or declaration: These can further be divided in 2 types
i<7 or condition: This is the keyword (reserved word) used to define.
i++ or increment: These represent the body of the if and else. when the condition is true, code withing if block will get execute or the code with within else block will get executed.
while: This is the keyword (reserved word) used to define.

As you can see the condition is checked at the end, the content of the loop will always execute at-least once (even when the condition is false).