how to update tax amount with custom price in magento 2

Question

HOW TO UPDATE TAX WITH CUSTOM VALUE IN CART OR CHECKOUT.My requirement was when customer click add to cart and he move to cart that time i want to update tax with some API so do the needful.

Answer 1

One approach is :

You can try to overide the default collect total tax function.

Add this dependency :

<preference for="Magento\Tax\Model\Sales\Total\Quote\Tax" type="Vendor\Module\Model\Tax\Sales\Total\Quote\Tax"/>

Create you own Quote Tax Collection function based on native one.

Add your logic inside the collect function.

Example :

/**
 * Custom Collect tax totals for quote address
 *
 * @param Quote $quote
 * @param ShippingAssignmentInterface $shippingAssignment
 * @param Address\Total $total
 * @return $this
 * @throws RemoteServiceUnavailableException
 */
public function collect(
    Quote $quote,
    ShippingAssignmentInterface $shippingAssignment,
    Address\Total $total
) {
    $address = $shippingAssignment->getShipping()->getAddress();

    $storeId = $quote->getStoreId();

    if ($this->doNotUseCustomTax()
    ) {
        return parent::collect($quote, $shippingAssignment, $total);
    }

    $this->processCustomTax($quote);

    return $this;
}