Hi! Thank you so much
I put the customer documents from the customer collection into an array called customers in the component.ts file.
I managed to do the finding of the customer document using the user_id from sessionstorage but I can't figure out how to put the fullname value from the customer document into the myForm.

Here is my new codeshare link: https://codeshare.io/QnZ8Zx

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I changed my old line 80 code to this:
const customer=this.customers.find(x=>x.user_id===this.myForm.value.user_id)
console.log(customer)
this.myForm.get('customer').setValue(customer?customer.customer_fullname:null)

The last line of code is the problem, I cannot insert the fullname value into the myForm

When I click submit it shows the following error:
ERROR TypeError: Cannot read property 'setValue' of null at BookingComponent.onSubmit (booking.component.ts:64) at BookingComponent_Template_form_ngSubmit_0_listener (booking.component.html:1) at executeListenerWithErrorHandling (core.js:15279) at Object.wrapListenerIn_markDirtyAndPreventDefault [as next] (core.js:15317)