Dynamic form Issue in Angular - forms

Question

Scenario :
A form is generated dynamically, I used this tutorial to create the form dynamically. When I click "Submit" button, the form value I get in the component is
ts :
doSubmitICR(form) {
console.log(form.value);
}
form.value has the following values
{
CaptainPoint:"0",
Category:"restaurant",
Description:"Test",
DisplayDept:"kitchen",
Group:"restaurant",
GuestPoint:"0",
ItemCode:"1",
ItemName:"Test Item",
PrintingDept:"frontoffice",
SalesRate:"3",
SubGroup:"restaurant",
TAX1:true,
TAX2:true,
TabDisplay:"restaurant",
Unit:"restaurant"
}
TAX1 and TAX2 are dynamic, those form controls were created from a tax table, If the table has TAX3 and TAX4, then instead of TAX1 and TAX2 in the above form, TAX3 and TAX4 form control is generated.
Issue :
If the TAXs are dynamic, how can I pass these values to Web service say WebAPI2 as a model?
Is it possible to filter only the TAX element from the form.value?
Any advice would be appreciated. Thank you.

Answer 1

The solution from alexKhymenko should work well. Alternatively, if the values you want to submit to the API will always have the format of TAX{d}, where d is some combination of digits, you could use the following to get just those values on a request object:
let request = {};
Object.keys(form.value).forEach(key => {
if(/^TAX[\d]+$/.test(key))
request[key] = form.value[key]
});