JavaScript Recursion

Recursion is a technique where a function calls itself to solve smaller instances of the same problem until a specific condition called the base case is met. It’s commonly used when a task can be broken down into repeated sub-tasks.

A recursive function must always have two parts:

• Base case: Defines when the recursion should stop to prevent infinite calls.
• Recursive call: The function calls itself to continue solving the smaller problem until the base case is reached.

If the base case is missing, the function will keep calling itself indefinitely, causing a stack overflow error.

Syntax

function recursiveFunction() {
  // Code block to execute
  recursiveFunction(); // Recursive call
}

Example

In this example, the function prints numbers from 1 to 10 by calling itself until a condition is met:

let count = 0;

function countToTen() {
  if (count < 10) {
    count = count + 1;
    console.log(count);
    countToTen(); // Recursive call
  }
}

countToTen();

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The output would be:

1
2
3
4
5
6
7
8
9
10

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Here’s what happens step by step:

• A variable count is initialized outside the function.
• The function checks if count is less than 10.
• If true, it increments count, prints it, and calls itself again.
• When count reaches 10, the base case condition fails, and recursion stops.

This process is similar to how loops work, but recursion uses function calls instead of loop structures.

Codebyte Example

In this example, the function repeatedly calls itself to print numbers from 1 to 10, stopping once the base case condition (count < 10) is no longer true:

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