Typescript - Learn while loop examples

In this tutorial, we’ll explore while loops in TypeScript through examples. TypeScript provides two versions of while loops:

• How to write a while loop in TypeScript?
• How to use a do-while loop in TypeScript?

#While Loop in TypeScript

Like every programming language, TypeScript offers a while loop. A while loop executes the statements within its code block as long as the conditional expression evaluates to true. If the expression is false, the code block is skipped.

while is a reserved keyword in TypeScript. This loop is commonly used for iterating over collections such as objects, arrays, sets, and maps.

Syntax:

while (conditionalExpression) {
  // Code block statements
}

#Finite Example of a while Loop

This example 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 a While Loop with an Example?

The break keyword allows you to exit from the execution of a while loop. It is used when a certain conditional expression is true.

Syntax:

break;

Here’s an example:

let counter = 1;
while (counter <= 6) {
  if (counter % 3 == 0) {
    console.log("IF Condition met");
    break; // The while loop exits here when the first number divisible by 3 is encountered
  }
  counter++;
}

Output:

IF Condition met

#while loop Infinite Example

An infinite loop occurs when the conditional expression is always true.

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

Output:

Infinite loop
Infinite loop
Infinite loop

#How to Use Async and Await in a While Loop?

async and await are used for handling asynchronous operations. Here’s an example.

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

By marking getRecords as async, we can use await within the loop to pause execution until a promise is fulfilled.

While loop works same with these async and await .

#Conclusion

In conclusion, we’ve covered while looping in TypeScript with examples, including both finite and infinite scenarios, the usage of the break keyword, and examples involving async and await.