Add ability to save current state into local storage

src/App.tsx

@@ -1,11 +1,25 @@
 import React from 'react'
 import InvoicePage from './components/InvoicePage'
+import { Invoice } from './data/types'
 
 function App() {
+  const savedInvoice = window.localStorage.getItem('invoiceData')
+  let data = null
+
+  try {
+    if (savedInvoice) {
+      data = JSON.parse(savedInvoice)
+    }
+  } catch (_e) { }
+
+  const onInvoiceUpdated = (invoice: Invoice) => {
+    window.localStorage.setItem('invoiceData', JSON.stringify(invoice))
+  }
+
   return (
     <div className="app">
       <h1 className="center fs-30">React Invoice Generator</h1>
-      <InvoicePage />
+      <InvoicePage data={data} onChange={onInvoiceUpdated} />
     </div>
   )
 }

src/components/InvoicePage.tsx

@@ -26,9 +26,10 @@ Font.register({
 interface Props {
   data?: Invoice
   pdfMode?: boolean
+  onChange?: (invoice: Invoice) => void
 }
 
-const InvoicePage: FC<Props> = ({ data, pdfMode }) => {
+const InvoicePage: FC<Props> = ({ data, pdfMode, onChange }) => {
   const [invoice, setInvoice] = useState<Invoice>(data ? { ...data } : { ...initialInvoice })
   const [subTotal, setSubTotal] = useState<number>()
   const [saleTax, setSaleTax] = useState<number>()
@@ -129,6 +130,12 @@ const InvoicePage: FC<Props> = ({ data, pdfMode }) => {
     setSaleTax(saleTax)
   }, [subTotal, invoice.taxLabel])
 
+  useEffect(() => {
+    if (onChange) {
+      onChange(invoice)
+    }
+  }, [onChange, invoice])
+
   return (
     <Document pdfMode={pdfMode}>
       <Page className="invoice-wrapper" pdfMode={pdfMode}>