Guide to implementing LeaderLine in Svelte

Question

Guide to implementing LeaderLine in Svelte

I'm a novice explorer of Svelte and I am experimenting with incorporating LeaderLine into a Svelte application. After successfully importing it using

import LeaderLine from 'leader-line';

, I encountered an issue with the example provided on the package page not functioning as expected:

<script>
  import LeaderLine from 'leader-line';

  new LeaderLine(
    document.getElementById('start'),
    document.getElementById('end')
  );    
</script>

<div id="start">start</div>
<div id="end">end</div>

I received this error in the browser console:

Uncaught (in promise) Error: start and end are required.

This problem seems to be related to the use of getElementById, which is generally discouraged in the context of Svelte development. I'd like to seek suggestions or solutions from the community on how to successfully integrate LeaderLine with Svelte. Any insights or ideas would be greatly appreciated!

javascript npm import svelte rollupjs

Answer 1

Answer №1

To ensure proper initialization of LeaderLine, it is important to wrap the code inside an onMount function. Running the script tag code before the component is added to the DOM can lead to document.getElementById('start') returning null. By using onMount, you can guarantee that the code will run after the component has been added to the DOM.

<script>
  import LeaderLine from 'leader-line';
  import { onMount } from 'svelte';

  onMount(() => {
    new LeaderLine(
      document.getElementById('start'),
      document.getElementById('end')
    );
  });
</script>

In Svelte, while you can use getElementId, it is more idiomatic to bind to the start and end elements for a cleaner approach.

<script>
  import LeaderLine from 'leader-line';
  import { onMount } from 'svelte';

  let start, end;
  onMount(() => {
    new LeaderLine(start, end);
  });
</script>

<div bind:this={start}>start</div>
<div bind:this={end}>end</div>

If you encountered the "start and end are required" error, you may need to configure Rollup with @rollup/plugin-legacy in order to build the app due to leader-line not exporting anything by default.

export default {
  // ... other config
  plugins: [
    // ... other plugins
    legacy({ 'node_modules/leader-line/leader-line.min.js': 'LeaderLine' }),
  ]
};

Answer 2

To ensure proper initialization of LeaderLine, it is important to wrap the code inside an onMount function. Running the script tag code before the component is added to the DOM can lead to document.getElementById('start') returning null. By using onMount, you can guarantee that the code will run after the component has been added to the DOM.

<script>
  import LeaderLine from 'leader-line';
  import { onMount } from 'svelte';

  onMount(() => {
    new LeaderLine(
      document.getElementById('start'),
      document.getElementById('end')
    );
  });
</script>

In Svelte, while you can use getElementId, it is more idiomatic to bind to the start and end elements for a cleaner approach.

<script>
  import LeaderLine from 'leader-line';
  import { onMount } from 'svelte';

  let start, end;
  onMount(() => {
    new LeaderLine(start, end);
  });
</script>

<div bind:this={start}>start</div>
<div bind:this={end}>end</div>

If you encountered the "start and end are required" error, you may need to configure Rollup with @rollup/plugin-legacy in order to build the app due to leader-line not exporting anything by default.

export default {
  // ... other config
  plugins: [
    // ... other plugins
    legacy({ 'node_modules/leader-line/leader-line.min.js': 'LeaderLine' }),
  ]
};

Guide to implementing LeaderLine in Svelte

Answer №1

Similar questions

Can you verify that the client's date and time locale are accurate in JavaScript before proceeding with processing?

Checking for partial matches in JavaScript using includes()

Can you explain the concept of "Import trace for requested module" and provide instructions on how to resolve any issues that

Accessing Ionic rootScope within the config stateprovider - A step-by-step guide

Guide on how to switch a class on the body using React's onClick event

What methods can be employed to maintain a consistent width for a multi-line span that aligns with the content?

Updating PHP query with JavaScript or jQuery: yea or nay?

Unable to remove webpack version 9.8.1 from my system

An error popped up: "argument list is missing) after"

Tips for aligning the dropdown menu to start from the border of the menu bar instead of displaying directly below the text

Struggling to insert a JavaScript variable into a MySQL database table using PHP and AJAX

Facing difficulties in installing certain dependencies in NodeJs projects

Switching over to the latest version of Material-UI, v1.x.x

Looking for a method to select a random value from an array of objects without having to go through the entire parent array?

Activate jQuery following the addition of fresh content

Implementing default header and footer with Angular's ui.router

Issue with Internet Explorer: Refusing to run javascript included in AJAX-loaded content

The div remains unchanged when the button is clicked

Organizing Parsed JSON Data with JavaScript: Using the _.each function for Sorting

Exploring Node.js: Managing Memory Consumption for Efficiency