refactor(front): extract shared utils and rewire pages

app/utils/events.ts

@@ -0,0 +1,41 @@
+/**
+ * Type-safe event handlers for form inputs.
+ * These helpers extract values from DOM events in a way that satisfies TypeScript.
+ */
+
+/**
+ * Extract the string value from an input event.
+ */
+export const getInputValue = (event: Event): string => {
+  const target = event.target as HTMLInputElement | null
+  return target?.value ?? ''
+}
+
+/**
+ * Extract the numeric value from an input event.
+ */
+export const getInputNumber = (event: Event): number => {
+  const target = event.target as HTMLInputElement | null
+  const value = target?.value ?? ''
+  const parsed = parseFloat(value)
+  return Number.isNaN(parsed) ? 0 : parsed
+}
+
+/**
+ * Extract the checked state from a checkbox event.
+ */
+export const getCheckboxValue = (event: Event): boolean => {
+  const target = event.target as HTMLInputElement | null
+  return target?.checked ?? false
+}
+
+/**
+ * Extract an optional numeric value from an input event (empty string = undefined).
+ */
+export const getOptionalNumber = (event: Event): number | undefined => {
+  const target = event.target as HTMLInputElement | null
+  const value = target?.value ?? ''
+  if (value.trim() === '') return undefined
+  const parsed = parseFloat(value)
+  return Number.isNaN(parsed) ? undefined : parsed
+}

app/utils/formatters/email.ts

@@ -20,8 +20,10 @@ export const maskEmail = (rawValue: string): string => {
     return ''
   }
 
-  const [localPart, domain] = value.split('@')
-  if (!domain) {
+  const parts = value.split('@')
+  const localPart = parts[0] ?? ''
+  const domain = parts[1]
+  if (!domain || !localPart) {
     return value
   }
 
@@ -29,7 +31,7 @@ export const maskEmail = (rawValue: string): string => {
     return `${localPart[0] ?? ''}·@${domain}`
   }
 
-  const start = localPart[0]
+  const start = localPart[0] ?? ''
   const end = localPart.slice(-1)
   const masked = '·'.repeat(Math.max(0, localPart.length - 2))