Tsoa validation doesn't work with long pattern values and validation messages

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Expected Behavior

Export type with long pattern added. Since the pattern string has a length bigger than 100 symbols (eslint max 100), pattern part moved to next line. Reject message moved to next line and starts from whitespace.

• Validation mechanism should use pattern from different rows and search for the regexp match.
• [e-mail] value should pass validation
• incorrectemail value should be rejected with message: Invalid email. Value is expected to match the pattern [a-zA-Z0-9.!#$%&'+/=?^_`{|}~-]+@a-zA-Z0-9?(?:.a-zA-Z0-9?)

/**
 * Stringified email.
 * See [RFC 1123](https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address).
 *
 * @pattern [a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?
 * (?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*
 *  Invalid email. Value is expected to match the pattern 
 * [a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9]
 * (?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9]
 * (?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*
 * 
 * @format email
 */
export type Email = string;

Current Behavior

• [e-mail] can’t pass validation, probably, because validation mechanism includes newline symbol into regexp expression.
• An error message omits first message word: email. Value is expected to match the pattern \n[a-zA-Z0-9.!#$%&'+/=?^_`{|}~-]+@[a-zA-Z0-9]\n(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9]\n(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)
• Multiline reject messages renders new line \n symbols.

Possible Solution

Steps to Reproduce

Use provided type

Context (Environment)

Version of the library: ^4.0.0-alpha.2 Version of NodeJS:

• Confirm you were using yarn not npm: [x ]

[ggbruno]

I made an implementation of the idea. It removes the newlines and allow the error message with double newlines.

https://github.com/ggbruno/tsoa/commit/2907652adf790c76ef9e365538c2ebb3a1a606d8

[igarioshka]

That’s a great idea! We can postprocess the error message in the function that handles validation errors, removing all unnecessary newlines. Now, only the pattern length would be difficult, as there would need to be a change in validatorUtils.