Magento 2 UI form set default value from url params?

Question

I want to set a form field value from the URL params in UI form. I am aware that static values can be set via default property of the field but how to set dynamic values as default (to be specific request URL params).

Also, what is the standard way to do it?

`http://localhost/magento/2.2.4/admin/mymodule/myform/edit/type/vendor/`

Here, type/vendor the value vendor needs to be set on type field as default.

<field name="type">
        <argument name="data" xsi:type="array">
            <item name="options" xsi:type="object">MyModule\MyVendor\Model\Source\Type</item>
            <item name="config" xsi:type="array">
                <item name="visible" xsi:type="boolean">true</item>
                <item name="dataType" xsi:type="string">select</item>
                <item name="formElement" xsi:type="string">select</item>
                <item name="source" xsi:type="string">mymodule_myform_form_data_source</item>
                <item name="label" xsi:type="string" translate="true">Type</item>
                <item name="disabled" xsi:type="boolean">true</item>
                <item name="default" xsi:type="string">inventory</item>
            </item>
        </argument>
    </field>

MyModule\MyVendor\Model\Source\Type.php

<?php

namespace MyModule\MyVendor\Model\Source;

use Magento\Eav\Model\Entity\Attribute\Source\AbstractSource;

class Type extends AbstractSource
{
    /**
     * @return array
     */
    public function getAllOptions()
    {
        return [
            [
                'value' => 'vendor',
                'label' => __('Vendor'),
            ],
        ];
    }
}

Answer 1

This is untested but you can give it a try.
In your Type.php class, inject \Magento\Framework\App\Request\Http $request to get the value of the parameter type in the URL which is the value vendor.

<?php

namespace MyModule\MyVendor\Model\Source;

class Type implements \Magento\Framework\Option\ArrayInterface
{
    protected $request;
    public function __construct(
        \Magento\Framework\App\Request\Http $request
    )
    {
        $this->request = $request;
    }
    public function toOptionArray()
    {
        $type = $this->request->getParam('type');

        return [
            [
                'value' => $type,
                'label' => __('Vendor'),
            ],
        ];

    }
}  

In that way, you are setting the value of options from the URL parameter.