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AssetSizeJavascript

Prevents using theme JavaScript files and external scripts with a compressed size greater than the configured threshold_in_bytes. Limiting the size of JavaScript files helps to improve the performance of your theme.

You occasionally might need to load large JavaScript bundles. In these cases, you can use an import on interaction pattern to avoid having users who don't interact with a component execute the bundle.

Anchor to ExamplesExamples

The following examples contain code snippets that either fail or pass this check.

Anchor to ✗ Fail✗ Fail

In the following example, assets/chat-widget.js is greater than 10 KB gzipped:

<script src="{{ 'chat-widget.js' | asset_url }}" defer></script>

Anchor to ✓ Pass✓ Pass

<script>
const chatWidgetButton = document.getElementById('#chat-widget')

chatWidgetButton.addEventListener('click', e => {
e.preventDefault();
import("{{ 'chat-widget.js' | asset_url }}")
.then(module => module.default)
.then(ChatWidget => ChatWidget.init())
.catch(err => {
console.error(err);
});
});
</script>

Anchor to OptionsOptions

The following example contains the default configuration for this check:

For themes:

AssetSizeJavaScript:
enabled: false
threshold_in_bytes: 10000

For theme app extensions:

AssetSizeJavaScript:
enabled: false
severity: suggestion
threshold_in_bytes: 10000
ParameterDescription
enabledWhether this check is enabled.
severityThe severity of the check.
threshold_in_bytesThe maximum allowed compressed size, in bytes, for a single JavaScript file. This includes the theme and remote scripts.

Anchor to Disabling this checkDisabling this check

This check is enabled by default when you run the Shopify CLI 3.x build command on an app that contains a theme app extension. This limit is not yet enforced, but disabling this check isn't recommended for theme app extensions.

If you can't avoid violating the rule, then you should disable the check using the comment syntax. This ensures that you intentionally disable the check for each instance.

{% # theme-check-disable AssetSizeJavaScript %}
<script src="{{ 'chat-widget.js' | asset_url }}" defer></script>
{% # theme-check-enable AssetSizeJavaScript %}

This check is disabled by default when you run the Shopify CLI 2.x shopify theme check command.

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