Constructor of Attribute doesn't match Drupal core

[JohnAlbin]

The current implementation of Attribute uses a JavaScript Map internally, which is an excellent choice.

But the constructor of Attribute just re-uses the Map constructor, so usage is:

const attr = new Attribute([['id', 'val'], ['class', ['one', 'two']]]);

or in a Twig file:

{% set attr = create_attribute([['id', 'val'], ['class', ['one', 'two']]]) %}

See the Map constructor docs:

Parameters
iterable (Optional)
An Array or other iterable object whose elements are key-value pairs. (For example, arrays with two elements, such as [[ 1, 'one' ],[ 2, 'two' ]].) Each key-value pair is added to the new Map.

But that doesn't match the syntax we'd use inside Drupal twig files because Twig associative arrays use an object-like syntax:

{% set attr = create_attribute({ id: "val", class: ["one", "two"]}) %}

I've implemented a work-around inside the create_attribute() Twig function.

The fault is either in:

• the Attribute constructor
• the JS Twig implementation that treats the object-like Twig syntax like an object.

We either need to provide a patch upstream or fork drupal-attribute into this project.

Docs for Drupal's Attribute object are here: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Template%21Attribute.php/class/Attribute/9.1.x

[JohnAlbin]

It looks like Twig.js converts the Twig associative array syntax into a JS object internally. And trying to pass an object to Attribute's constructor errors with object is not iterable (cannot read property Symbol(Symbol.iterator))

[MichaelAllenWarner]

Hi @JohnAlbin,

I think I have a fix for this, and also a way to get property-access working in both Twing and Twig.js (the {{ attributes.style }} syntax). It all builds on top of #53, though. Would it make sense for me to scrap #53 and replace it with one big PR that addresses all create_attribute() problems? Or would you rather I proceed incrementally?

[MichaelAllenWarner]

For context, here is my feature-branch that has all create_attribute() fixes: https://github.com/MichaelAllenWarner/drupal-twig-extensions/tree/fix-create_attributes

Diff: main...MichaelAllenWarner:drupal-twig-extensions:fix-create_attributes

(So the "big PR" would be for all this.)

[MichaelAllenWarner]

I went ahead and made the "big" PR (#54) and closed #53.