for tag does not support valueOf recognition in Drop

[maiyuanrdt]

Shopify Code example:

<ul> 
  {%- for field in form.errors -%}
    <li>
      {%- if field == 'form' -%}
        {{ form.errors.messages[field] }}
      {%- else -%}
        <a href="#RegisterForm-{{ field }}">
          {{ form.errors.translated_fields[field] | capitalize }}
          {{ form.errors.messages[field] }}
        </a>
      {%- endif -%}
    </li>
  {%- endfor -%}
</ul>

The above is the liquid code structure that outputs the error information in the form form in Shopify, in which for is used to traverse form.errors and use it as an index key.
The result of execution in Shopify is:

and

-------------------------------------------------------------problem lies in------------------------------------------------------------
Using liquidjs for simulation adaptation, it was found that the valueOf in Drop was not responded to.

class ErrorsDrop extends Drop {
    constructor() {
        super()
        this.password = 'pppp'
        this.email = 'eeee'
    }

    valueOf() {
        return ['xxx', 'ccc']
    }
}
const errors = new ErrorsDrop()
liquid.parseAndRender('-- This {{ name }}: {{errors}} -- {% for field in errors %} ={{ field }}= {% endfor %}', {
    name: 'valueOf',
    errors
})

I defined an object named ErrorsDrop, assigned it to the errors variable, and traversed the errors through the for tag, and got the following results:

-- This valueOf: xxxccc --  =passwordpppp=  =emaileeee= 

Personally think that when for in is followed by a Drop object, it should respond to the result after its valueOf(). Otherwise, writing similar to Shopify will not take effect

[maiyuanrdt]

@harttle Hi~

[harttle]

Try adding json filter as you’re in Shopify template

This {{ name }}: {{errors|json}} -- {% for field in errors %} ={{ field|json }}= {% endfor %}', {
    name: 'valueOf',

The way LiquidJS iterate objects can be different. I can try fix it as a bug.

[github-actions]

🎉 This issue has been resolved in version 9.39.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[harttle]

Try v9.39.0, now LiquidJS aligns with shopify in treating valueOf (to_liquid_value in Ruby):

c3e51ca#diff-a78edf8898b08c521478be171016452cfe322e302f08d167e0f931376b2e7d68R64-R74

For Drop iteration, maybe you're interested in this:

liquidjs/test/integration/builtin/tags/for.ts

Lines 321 to 330 in 4289b4e

	class MockIterableDrop extends Drop {
	* [Symbol.iterator] () {
	yield 'a'
	yield 'b'
	yield 'c'
	}
	toString () {
	return 'MockIterableDrop'
	}
	}

Note that if you decide to use valueOf, you'll have to implement the Symbole.iterator on the return value of valueOf.