How do I clear the FormArray in Angular Reactive Forms

Angular 8

simply use clear() method on formArrays :

(this.invoiceForm.controls['invoiceparticulars']).clear();

OR :

let frmArray = this.invoiceForm.get('invoiceparticulars') as FormArray;
frmArray.clear();

Try to add this code

const control = <FormArray>this.invoiceForm.controls['invoiceparticulars'];
        for(let i = control.length-1; i >= 0; i--) {
            control.removeAt(i)
    }