I had to do a light mini cart customizations to make it match the requirements. Magento 2 mini cart is based on HTML-template loaded and filled by the Knockout js-library. This task is quite complicated, especially for the beginners who haven’t got enough Magento 2 expertise.
Magento 2 Mini Cart Issues
Knockout js-library Knockout allows using html-templates instead of phtml-templates. Unfortunately, the visibility of the html-templates is worse than the visibility of phtml-templates. That’s how the part of the minicart.phtml template that displays a mini cart block on the screen looks like:
<div id="minicart-content-wrapper" data-bind="scope: 'minicart_content'"> <!-- ko template: getTemplate() --><!-- /ko --> </div>
The situation becomes more complicated when you reveal that there is no a getTemplate() function in the js-scripts of Magento_Checkout module.
Firstly, you have to determine what UI-element Knockout will be using for the DIV element. It’s obvious: required UI-element scope is specified directly in the data-bind attribute. If there’s no data-bind attribute, you have to check Magento configuration files to determine the UI-element. In this case, you can also use debugging methods. I’ll describe them below.
We know that getTemplate() function is called from the UI-element named minicart_content. The next step is to open the page source code and find the script that describes minicart_content and its child elements.
<script type="text/x-magento-init"> { "[data-block='minicart']": { "Magento_Ui/js/core/app": {"components":{"minicart_content":{"children":{"subtotal.container":{"children":{"subtotal":{"children":{"subtotal.totals": {"config":{"display_cart_subtotal_incl_tax":0,"display_cart_subtotal_excl_tax":1,"template":"Magento_Tax\/checkout\/minicart\/subtotal\/totals"},"children": {"subtotal.totals.msrp":{"component":"Magento_Msrp\/js\/view\/checkout\/minicart\/subtotal\/totals","config": {"displayArea":"minicart-subtotal-hidden","template":"Magento_Msrp\/checkout\/minicart\/subtotal\/totals"}}}, "component":"Magento_Tax\/js\/view\/checkout\/minicart\/subtotal\/totals"}},"component":"uiComponent","config": {"template":"Magento_Checkout\/minicart\/subtotal"}}},"component":"uiComponent","config":{"displayArea":"subtotalContainer"}},"item.renderer": {"component":"uiComponent","config":{"displayArea":"defaultRenderer","template":"Magento_Checkout\/minicart\/item\/default"},"children":{"item.image": {"component":"Magento_Catalog\/js\/view\/image","config":{"template":"Magento_Catalog\/product\/image","displayArea":"itemImage"}}, "checkout.cart.item.price.sidebar":{"component":"uiComponent","config": {"template":"Magento_Checkout\/minicart\/item\/price","displayArea":"priceSidebar"}}}},"extra_info":{"component":"uiComponent","config": {"displayArea":"extraInfo"}},"promotion":{"component":"uiComponent","config":{"displayArea":"promotion"}}},"config":{"itemRenderer": {"default":"defaultRenderer","simple":"defaultRenderer","virtual":"defaultRenderer"},"template":"Magento_Checkout\/minicart\/content"},"component": "Magento_Checkout\/js\/view\/minicart"}},"types":[]} }, "*": { "Magento_Ui/js/block-loader": "http://et.magenmagic.com/static/version1500468461/frontend/Magenmagic/ettage/en_US/images/loader-1.gif" } } </script>
There is an htmpl-template description which will be returned when the getTemplate() function is called:
"template":"Magento_Checkout\/minicart\/content" In this case, it means that the required template is located in vendor/magento/module-checkout/view/frontend/web/template/minicart/content.html
Debugging Methods
The hardest part of working on an html-template is that it doesn’t contain any information about UI-element that is used by the Knockout library for this template.
Phtml-templates also won’t provide you with this information. You don’t need to analyze configuration files to reveal it. All you need is to set a breakpoint in the template, enable the debugger and check what block is hidden under the variable $this.
Setting a breakpoint in the html-template isn’t a suitable method since the Knockout library fills templates with information. In this case, the breakpoint won’t work.
I’ll share with you some other debugging methods which don’t require exhausting Magento configuration files examining.
Debugging Method #1
The first method is inserting a console.log command into the data-bind attribute.
Let’s take a look at it in html-template vendor/magento/module-checkout/view/frontend/web/template/minicart/content.html:
<div class="block-content"> <button type="button" id="btn-minicart-close" class="action close" data-action="close" data-bind="attr: { title: $t('Close') }"> <span translate="'Close'"/> </button> <if args="getCartParam('summary_count')"> <div class="items-total">
Here is the block <if args=”getCartParam(‘summary_count’)”>
The block <if> inside the div-element <div class=”block-content”> is a Magento invention. It equals the Knockout command <!– ko if: getCartParam(‘summary_count’) –>
We need to know the UI-element that calls the getCartParam method. It’s the time to insert console.log command into the data-bind attribute.
We rewrite the code fragment in the following way:
<div class="block-content" data-bind="uniqueName: console.log($data)"> <button type="button" id="btn-minicart-close" class="action close" data-action="close" data-bind="attr: { title: $t('Close') }"> <span translate="'Close'"/> </button> <if args="getCartParam('summary_count')"> <div class="items-total">
We change only the first line. As a result, we can see the following info in a browser console while page loading:
UiClass {_super: undefined, ignoreTmpls: {…}, _requesetd: {…}, containers: Array(0), exports: {…}, …}
component:"Magento_Checkout/js/view/minicart"
containers:[]
dataScope:""
elems:ƒ observable()
exports:{}
extendProvider:true
hasUnique:undefined
ignoreTmpls:{templates: true, childDefaults: true}
imports:{}
index:"minicart_content"
initChildCount:4
itemRenderer:{default: "defaultRenderer", simple: "defaultRenderer", virtual: "defaultRenderer"}
links:{}
listens:{}
maps:{imports: {…}, exports: {…}}
modules:{storage: "localStorage"}
name:"minicart_content"
ns:"minicart_content"
parentName:""
parentScope:""
provider:""
regions:{subtotalContainer: ƒ, defaultRenderer: ƒ, extraInfo: ƒ, promotion: ƒ, sign-in-popup: ƒ}
registerNodes:true
source:undefined
statefull:{}
storage:ƒ ()
storageConfig:{provider: "localStorage", namespace: "minicart_content", path: "localStorage:minicart_content"}
template:"Magento_Checkout/minicart/content"
tracks:{}
_elems:(4) [UiClass, UiClass, UiClass, UiClass]
_requesetd:{localStorage: ƒ}
_super:undefined
__proto__:UiClass
Now we have the detailed info on UI-element that is used to fill the html-template with data. This UI-element calls the getCartParam (‘summary_count’) method.
At last, we need to check the result that the method’s calling returns.
Debugging Method #2
We have info on UI-element and we need to check the returning result of the getCartParam method.
We need a link to the UI-element to do it. All of UI-elements links are stored in the registry. Run the reg = requirejs(‘uiRegistry’); command in your browser.
After the debugging info analysis on UI-element, we see the following line: index:“minicart_content“
We can easily get the link to the UI-element in the registry using this index. Run the command in your browser: longDesiredReference = reg.get(‘minicart_content’)
Now, we can test the calling of any method of the UI-element in a browser, including the getCartParam: longDesiredReference.getCartParam(‘summary_count’) method
Extra information
As we saw in the example of using the <if args=”getCartParam(‘summary_count’)”> element, Magento developers decided to extend the capabilities of calling Knockout library with the new elements.
Using these elements isn’t a necessity. You can use standard Knockout elements like <!– ko if: getCartParam(‘summary_count’) –>
Nevertheless, Magento elements look better on an IDE screen because they are more contrast than standard Knockout elements.
If you need more info about Magento 2 and Knockout integration check the Alan Storm’s article.
You can also visit our blog to discover the latest eCommerce trends, news and tips.
Magento Developer at Mobecls
6+ years of experience
Feel free to ask me anything about this post in the comments below