Store amounts as cents

src/app/groups/[groupId]/balances-list.tsx

@@ -15,51 +15,38 @@ export function BalancesList({ balances, participants, currency }: Props) {
 
   return (
     <div className="text-sm">
-      {participants.map((participant) => (
-        <div
-          key={participant.id}
-          className={cn(
-            'flex',
-            balances[participant.id]?.total >= 0 || 'flex-row-reverse',
-          )}
-        >
+      {participants.map((participant) => {
+        const balance = balances[participant.id]?.total ?? 0
+        const isLeft = balance >= 0
+        return (
           <div
-            className={cn(
-              'w-1/2 p-2',
-              balances[participant.id]?.total >= 0 && 'text-right',
-            )}
+            key={participant.id}
+            className={cn('flex', isLeft || 'flex-row-reverse')}
           >
-            {participant.name}
-          </div>
-          <div
-            className={cn(
-              'w-1/2 relative',
-              balances[participant.id]?.total >= 0 || 'text-right',
-            )}
-          >
-            <div className="absolute inset-0 p-2 z-20">
-              {currency} {(balances[participant.id]?.total ?? 0).toFixed(2)}
+            <div className={cn('w-1/2 p-2', isLeft && 'text-right')}>
+              {participant.name}
+            </div>
+            <div className={cn('w-1/2 relative', isLeft || 'text-right')}>
+              <div className="absolute inset-0 p-2 z-20">
+                {currency} {(balance / 100).toFixed(2)}
+              </div>
+              {balance !== 0 && (
+                <div
+                  className={cn(
+                    'absolute top-1 h-7 z-10',
+                    isLeft
+                      ? 'bg-green-200 left-0 rounded-r-lg border border-green-300'
+                      : 'bg-red-200 right-0 rounded-l-lg border  border-red-300',
+                  )}
+                  style={{
+                    width: (Math.abs(balance) / maxBalance) * 100 + '%',
+                  }}
+                ></div>
+              )}
             </div>
-            {balances[participant.id]?.total !== 0 && (
-              <div
-                className={cn(
-                  'absolute top-1 h-7 z-10',
-                  balances[participant.id]?.total > 0
-                    ? 'bg-green-200 left-0 rounded-r-lg border border-green-300'
-                    : 'bg-red-200 right-0 rounded-l-lg border  border-red-300',
-                )}
-                style={{
-                  width:
-                    (Math.abs(balances[participant.id]?.total ?? 0) /
-                      maxBalance) *
-                      100 +
-                    '%',
-                }}
-              ></div>
-            )}
           </div>
-        </div>
-      ))}
+        )
+      })}
     </div>
   )
 }

src/app/groups/[groupId]/expenses/expense-list.tsx

@@ -53,7 +53,7 @@ export function ExpenseList({
         </div>
         <div className="flex items-center">
           <div className="tabular-nums whitespace-nowrap font-bold">
-            {currency} {expense.amount.toFixed(2)}
+            {currency} {(expense.amount / 100).toFixed(2)}
           </div>
           <Button size="icon" variant="link" className="-my-2" asChild>
             <Link href={`/groups/${groupId}/expenses/${expense.id}/edit`}>

src/app/groups/[groupId]/reimbursement-list.tsx

@@ -16,6 +16,14 @@ export function ReimbursementList({
   currency,
   groupId,
 }: Props) {
+  if (reimbursements.length === 0) {
+    return (
+      <p className="px-6 text-sm pb-6">
+        It looks like your group doesn’t need any reimbursement 😁
+      </p>
+    )
+  }
+
   const getParticipant = (id: string) => participants.find((p) => p.id === id)
   return (
     <div className="text-sm">
@@ -35,7 +43,7 @@ export function ReimbursementList({
             </Button>
           </div>
           <div>
-            {currency} {reimbursement.amount.toFixed(2)}
+            {currency} {(reimbursement.amount / 100).toFixed(2)}
           </div>
         </div>
       ))}

src/app/groups/[groupId]/save-recent-group.tsx

@@ -12,7 +12,7 @@ type Props = {
 export function SaveGroupLocally({ group }: Props) {
   useEffect(() => {
     saveRecentGroup(group)
-  }, [])
+  }, [group])
 
   return null
 }

src/components/expense-form.tsx

@@ -47,7 +47,7 @@ export function ExpenseForm({ group, expense, onSubmit, onDelete }: Props) {
     defaultValues: expense
       ? {
           title: expense.title,
-          amount: expense.amount,
+          amount: String(expense.amount / 100) as unknown as number, // hack
           paidBy: expense.paidById,
           paidFor: expense.paidFor.map(({ participantId }) => participantId),
           isReimbursement: expense.isReimbursement,
@@ -55,7 +55,9 @@ export function ExpenseForm({ group, expense, onSubmit, onDelete }: Props) {
       : searchParams.get('reimbursement')
       ? {
           title: 'Reimbursement',
-          amount: Number(searchParams.get('amount')) || 0,
+          amount: String(
+            (Number(searchParams.get('amount')) || 0) / 100,
+          ) as unknown as number, // hack
           paidBy: searchParams.get('from') ?? undefined,
           paidFor: [searchParams.get('to') ?? undefined],
           isReimbursement: true,

src/lib/balances.ts

@@ -42,7 +42,7 @@ export function getBalances(
 }
 
 function divide(total: number, count: number, isLast: boolean): number {
-  if (!isLast) return Math.floor((total * 100) / count) / 100
+  if (!isLast) return Math.floor(total / count)
 
   return total - divide(total, count, false) * (count - 1)
 }
@@ -58,7 +58,7 @@ export function getSuggestedReimbursements(
   while (balancesArray.length > 1) {
     const first = balancesArray[0]
     const last = balancesArray[balancesArray.length - 1]
-    const amount = Math.round(first.total * 100 + last.total * 100) / 100
+    const amount = first.total + last.total
     if (first.total > -last.total) {
       reimbursements.push({
         from: last.participantId,
@@ -77,5 +77,5 @@ export function getSuggestedReimbursements(
       balancesArray.shift()
     }
   }
-  return reimbursements
+  return reimbursements.filter(({ amount }) => amount !== 0)
 }

src/lib/schemas.ts

@@ -42,9 +42,27 @@ export const expenseFormSchema = z.object({
   title: z
     .string({ required_error: 'Please enter a title.' })
     .min(2, 'Enter at least two characters.'),
-  amount: z.coerce
-    .number({ required_error: 'You must enter an amount.' })
-    .min(0.01, 'The amount must be higher than 0.01.'),
+  amount: z
+    .union(
+      [
+        z.number(),
+        z.string().transform((value, ctx) => {
+          const valueAsNumber = Number(value)
+          if (Number.isNaN(valueAsNumber))
+            ctx.addIssue({
+              code: z.ZodIssueCode.custom,
+              message: 'Invalid number.',
+            })
+          return Math.floor(valueAsNumber * 100)
+        }),
+      ],
+      { required_error: 'You must enter an amount.' },
+    )
+    .refine((amount) => amount >= 1, 'The amount must be higher than 0.01.')
+    .refine(
+      (amount) => amount <= 10_000_000_00,
+      'The amount must be lower than 10,000,000.',
+    ),
   paidBy: z.string({ required_error: 'You must select a participant.' }),
   paidFor: z
     .array(z.string())