Typescript - Learn while loop examples

In this tutorial, learn while looping in typescript with examples.

While Loop in typescript

As every programming language provides a while loop.

While loop executes the statements of the code block for true conditional expression. It first evaluates the conditional expressions, and if they are ’true,’ the Code block is executed. Otherwise, the code enclosed within the while loop is not executed. while is a keyword in typescript. This Loop is used to iterate over a collection of ‘objects’ or ‘arrays,’ as well as ‘set’ and ‘Map.’

Syntax:

while (Conditional Expression){  
//Code block statements  
}  

while loop Finite example

This iterates the loop 5 times and outputs a counter to the console log

let counter = 1;
while (counter <= 5) {
  console.log(counter);
  counter++;
}

Output:

1  
2  
3  
4  
5  

How to use the Break keyword in the while loop with an example?

The Break keyword is used to exit from the while loop execution.

It is used when some conditional expression is true
Syntax:

break;  

Here is an example

let counter = 1;
while (counter <= 6) {
  if (counter % 3 == 0) {
    console.log("IF Condition met");
    break; //While loop exit here for the first matched number divided by 3 is zero
  }
  counter++;
}

Output:

IF Condition met  

while loop Infinite Example

An infinite loop is executed when the Conditional expression is configured with true.

while (true) {
  console.log("Infinite loop");
}

Output:

Infinite loop  
Infinite loop  
Infinite loop  

How to use async and await in the while loop?

async and await are used for asynchronous operations. let’s see an example

const getRecords = async (_) => {
  let isFlag = false;
  while (!isFlag) {
    let res = await fetch("/api/get");
    if (res.status === 200) isFlag = true;
  }
};

The getRecords method added the async keyword.

Calling these methods pauses the execution of await operation until a promise response is fulfilled.

while loop works as same with conditional expression

Conclusion

To sum up, We learned while looping in typescript with an example with infinite and finite use cases and break keywords. It also includes async and await examples.