Ends With

Validates that a value ends with a given suffix string.

Configuration

Config flag	Type	Description
`endsWith`	`string`	The required suffix.
`endsWith`	`[string, string]`	Tuple form — the suffix plus a custom message.

const form = useForm({
  initialValues: { file: '' },
  validationSchema: {
    file: { endsWith: '.csv' },
  },
});

With a custom message:

file: { endsWith: ['.csv', 'Only CSV exports are allowed'] }

import { V } from 'formify-js';

V.endsWith('.csv');

Scenario	Message
Value does not end with the suffix	`Must end with ".csv"` (the message names your suffix)

Value	Rule	Result
`'report.csv'`	`endsWith: '.csv'`	✅ Valid
`'report.xlsx'`	`endsWith: '.csv'`	❌ Invalid

The check is case-sensitive: 'report.CSV' fails when the suffix is '.csv'.
For file uploads, fileExtension is often a cleaner fit — it checks the extension list rather than the raw string.