Error Handling

Validation Methods

Vex provides three ways to handle validation:

1. Direct Call (Throws)

import { str, email, ValidationError } from '@sylphx/vex'

const schema = str(email)

try {
  schema('invalid')
} catch (e) {
  if (e instanceof ValidationError) {
    console.log(e.message) // "Invalid email"
  }
}

2. safeParse (Returns Result)

import { str, email, safeParse } from '@sylphx/vex'

const schema = str(email)
const result = safeParse(schema)('invalid')

if (!result.success) {
  console.log(result.error) // "Invalid email"
} else {
  console.log(result.data)  // typed value
}

3. tryParse (Returns null on error)

import { str, email, tryParse } from '@sylphx/vex'

const schema = str(email)
const value = tryParse(schema)('invalid')

if (value === null) {
  console.log('Validation failed')
}

Error Messages

Object Errors

Errors include field paths:

import { object, str, num, safeParse } from '@sylphx/vex'

const schema = object({
  user: object({
    email: str(email),
  }),
})

const result = safeParse(schema)({
  user: { email: 'invalid' }
})

if (!result.success) {
  console.log(result.error)
  // "user.email: Invalid email"
}

Array Errors

Errors include array indices:

import { array, str, email, safeParse } from '@sylphx/vex'

const schema = array(str(email))

const result = safeParse(schema)(['a@b.com', 'invalid', 'c@d.com'])

if (!result.success) {
  console.log(result.error)
  // "[1]: Invalid email"
}

ValidationError

import { ValidationError } from '@sylphx/vex'

try {
  schema(data)
} catch (e) {
  if (e instanceof ValidationError) {
    console.log(e.message) // error message
    console.log(e.path)    // error path (if available)
  }
}

Error Handling

On this page