Gutenberg Cart block

[alexmigf]

closes #19

Steps to add the cart to the navigation block

1. On the navigation block click the + button to add a new link:

2. Click the custom link button and select Cart:

3. The link should be converted to the Cart navigation block:

Technical considerations

I needed to change the block type from static to dynamic because when the cart contents change the block triggers an error in the editor (image below), content can't be changed using static blocks.

Gutenberg knows this is dynamic block by returning null on the save function:

save: function() {
	// return null to render from php
	return null;
},

I discover also that dynamic blocks can be rendered from PHP using ServerSideRender.

This block is a children from parent: [ 'core/navigation' ], and has a transform property that converts from core/navigation-link to our block:

transforms: {
	from: [
		{
			type:      'block',
			blocks:    [ 'core/navigation-link' ],
			transform: () => createBlock( 'wpo/wpmenucart-navigation' )
		}
	]
},

I have also fixed an issue loading the cart on the full site editor, where the session was returning null.

[Spreeuw]

Great work, just one minor comment! 💪

[dpeyou]

No new issues to report!

[dwalkerpriv]

Same here. prior fatal errors about regarding Session are gone. cart loads and behaves normally on it's pages

[YordanSoares]

✔️ Looks good to me! Now the menu cart follows the Show on cart & checkout page setting, as well as the Always display cart, even if it's empty and Display shopping cart icon settings.