Is it possible to trigger eager-loading of transforms for an asset that has already been eager-loaded?

[BigglesZX]

I'm used to eager-loading Matrix and Asset fields by specifying them as part of an eagerLoadElements call in my templates like this:

{% do craft.app.elements.eagerLoadElements(
    className(entry),
    [entry],
    [
        'myMatrixField',
        'myMatrixField.blockType:assetField',
    ])
%}

I'm starting to implement eager-loading for asset transforms, and it would be more maintainable for me to trigger that eager-loading inside the Twig components that render the picture and img elements, rather than at the page template level, as the components have more specific knowledge of which transforms are needed.

Just as I can trigger eager-loading of entry fields at any time using the {% do craft.app.elements.eagerLoadElements(...) %} syntax as above, is there a way to trigger eager-loading of asset transforms directly from the asset, i.e. when working with an asset object that has itself already been eager-loaded? At the moment my understanding is that it can only be done at the same time as eager-loading the asset field itself.

I'm thinking something like this:

{# Warning: fictional! #}
{% do craft.app.elements.eagerLoadAssetTransforms(
    className(entry.myMatrixField[0].assetField[0]),
    [entry.myMatrixField[0].assetField[0]],
    [
        'square',
        { width: 200, height: 100 },
    ])
%}

Is that currently possible? Am I missing something obvious? I suppose I could pass an instance of an AssetField into my components instead of an Asset (so I could then call .withTransforms() on the field), but it seems preferable not to do that. Any tips would be very much appreciated!

[BigglesZX]

I've just found the eagerLoadTransforms method of the AssetTransforms service class, which seems like it might do what I want, but I'm not sure that service is accessible from the template. I'll keep digging...

[brandonkelly]

Yep, that’s the one.

{% do craft.app.assetTransforms.eagerLoadTransforms([asset], [
    'square',
    '...',
]) %}

Worth noting that you’re not fully solving N+1 problems when you put off eager-loading until this point though. The whole idea with eager-loading is you do it as early as possible, so you aren’t querying for elements/transforms multiple times.

[BigglesZX]

Thanks @brandonkelly! Straight on it as always. Noted your point about N+1 – I’ll have to have a think about the tradeoff of complex template-level eager-loading plan vs excess queries from the component level.

[BigglesZX]

Just a note that in Craft 4 the eagerLoadTransforms method is now part of the ImageTransforms service – the AssetTransforms service has been removed.

{% do craft.app.imageTransforms.eagerLoadTransforms([asset], [
    'square',
    '...',
]) %}