Validation

Validation rules stay on the same field chain as its stored type:

const amount = bd
  .number()
  .required()
  .validate({
    greaterThan: 0,
    lessThan: 10000,
    positive: true,
    round: 2,
  })

Successive validation modifiers merge into one ValidationRules object:

const code = bd
  .text()
  .validate({ minLength: 6, maxLength: 12 })
  .regex(/^[A-Z][A-Z0-9_-]+$/)

For the distinction between rule definitions, current errors, and server validation, read Validation and Form State.

Presence rules

Rule or modifier	Behavior
`.required()`	Schema declaration: `isRequired: true`, `isNullable: false`
`.optional()`	Schema declaration: `isRequired: false`, `isNullable: true`
`notNull`	`validateFieldValue()` rejects `null`, `undefined`, and `''`
`requiredIf`	Rejects an empty value when sibling context matches

const purchaseOrder = bd.text().requiredIf({
  fieldRef: 'paymentMethod',
  op: 'equals',
  values: ['invoice'],
})

requiredIf accepts equals or notEquals.

Length and pattern rules

Rule	Applies to	Behavior
`minLength`	`TEXT`, `ARRAY`	Minimum characters or entries
`maxLength`	`TEXT`, `ARRAY`	Maximum characters or entries
`regex`	String values	Tests a `RegExp` or regex source string

Numeric constraints

Rule	Applies to	Behavior
`greaterThan`	Numeric values	Strict lower bound (`>`)
`lessThan`	Numeric values	Strict upper bound (`<`)
`positive`	`NUMBER`, `NUMERIC`	Rejects values below zero; zero passes in 0.9.50
`isDecimal`	`NUMBER`, `NUMERIC`	Requires a non-zero fractional component

Numeric transforms

Rule	Applies to	Behavior
`round`	`NUMBER`, `NUMERIC`	Rounds to the configured decimal places
`floor`	`NUMBER`, `NUMERIC`	Applies `Math.floor()`

Transforms return their normalized number through result.value:

const result = validateFieldValue(12.345, { round: 2 })

if (result.valid) {
  save(result.value) // 12.35
}

Date rules

Rule	Behavior
`lessThanToday`	Date must be strictly before local start-of-today
`greaterThanToday`	Date must be strictly after local start-of-today
`specificDateValue: 'today()'`	Parsed timestamp must equal local start-of-today

SpecialDateValue also accepts a string or Date, but the 0.9.50 runtime does not compare those forms. Use the three enforced forms above when relying on validateFieldValue().

Definition-time checks

createSchema() rejects invalid combinations before an artifact is produced:

length rules on a type other than TEXT or ARRAY,
negative lengths or minLength > maxLength,
greaterThan >= lessThan,
numeric math rules on non-numeric fields,
a negative or fractional round,
floor together with round,
floor or round together with isDecimal,
both lessThanToday and greaterThanToday.

These failures describe an invalid developer definition. They are not visitor-facing field errors.

Validate one field

import { validateFieldValue } from '@businessdash/sdk'

const result = validateFieldValue(
  undefined,
  {
    requiredIf: {
      fieldRef: 'paymentMethod',
      op: 'equals',
      values: ['invoice'],
    },
  },
  { paymentMethod: 'invoice' },
)

The return type is:

{
  valid: boolean
  value: unknown
  error?: string
}

An empty value passes unless notNull or a matching requiredIf requires it.

Measurement validation

validateAndResolveMeasurement() checks the number, decimal policy, and fixed unit membership for a measurement definition:

const result = validateAndResolveMeasurement(
  { value: 125, unit: 'cm' },
  {
    category: 'length',
    unitPicker: 'fixed',
    default_unit: 'cm',
    resolve_to_your_unit: 'cm',
    allow_decimals: true,
  },
)

SQL check metadata

const balance = bd.number().check('balance >= 0')

.check() stores validation.checkExpression. validateFieldValue() does not execute SQL or evaluate that expression.

Published-form validation is separate

validateFormSubmission(schema, data) validates data against the dashboard-authored FormSchema returned by forms.schema(slug). It does not take a ValidationRules object or uiFormTree.

The Live server validates again during submission and remains authoritative.

Next: Form Elements.