How to Loop Each Block X Amount of Times in Svelte?

Svelte is a modern JavaScript framework that offers a unique approach to building web applications by compiling components at build time. One common requirement in web development is iterating over a block of code a specific number of times. In Svelte, this can be achieved using the {#each} block. This article will explore different methods to loop a block X amount of times in Svelte, complete with syntax, examples, and output.

In Svelte, the {#each} block is typically used to iterate over arrays or objects. However, there are scenarios where you might want to repeat a block of code a specific number of times without an existing array to loop over. This can be achieved by creating an array of a certain length or by using helper functions. Below, we will discuss various methods to loop a block X amount of times in Svelte.

These are the following approaches to loop each block X amount of times in Svelte:

Steps to Create Svelte Application

Step 1: Initialize a New Svelte Project

npm create svelte@latest my-svelte-app
cd my-svelte-app
npm install

To implement these approaches, you'll typically have the following folder structure in your Svelte application:

Step 2: Modify App.svelte

Replace the contents of src/App.svelte with the following code:

<script>
  let X = 5;
</script>

<h1>Looping {X} Times</h1>

{#each Array.from({ length: X }) as _, index}
  <p>This is iteration number {index + 1}</p>
{/each}

<style>
  h1 {
    color: #ff3e00;
  }
  p {
    font-size: 1.2em;
  }
</style>

Step 3: Run the Application

npm run dev

Output:

Using Array.from() Method

The Array.from() method creates a new, shallow-copied array instance from an array-like or iterable object. By passing an object with a length property, you can create an array of a specific length and iterate over it using the {#each} block.

Syntax:

{#each Array.from({ length: X }) as _, index}
  <!-- Code to be repeated -->
{/each}

Example: Let's loop a block 5 times and display the iteration number.

// src/App.svelte

<script>
  let X = 5;
</script>

{#each Array.from({ length: X }) as _, index}
  <p>This is iteration number {index + 1}</p>
{/each}

Output:

Using a Range Function

Creating a helper range() function can offer more control over the loop. This function generates an array of numbers within a specified range, which can then be used in the {#each} block.

Syntax:

<script>
  function range(size) {
    return [...Array(size).keys()];
  }
</script>

{#each range(X) as index}
  <!-- Code to be repeated -->
{/each}

Example: Looping 5 times using the range() function.

// src/App.svelte
<script>
  let X = 5;

  function range(size) {
    return [...Array(size).keys()];
  }
</script>

{#each range(X) as index}
  <p>This is iteration number {index + 1}</p>
{/each}

Output:

Using Reactive Statements

Reactive statements in Svelte allow you to automatically update values when their dependencies change. By creating a reactive array based on X, you can dynamically control the number of iterations in your loop.

Syntax:

<script>
  let X = 5;
  $: loopArray = Array.from({ length: X });
</script>

{#each loopArray as _, index}
  <!-- Code to be repeated -->
{/each}

Example: Using a reactive statement to loop 5 times.

// src/App.svelte
<script>
  let X = 5;
  $: loopArray = Array.from({ length: X });
</script>

{#each loopArray as _, index}
  <p>This is iteration number {index + 1}</p>
{/each}

Output: