pipe

Adds rules and transforms to a schema. They run in order after the type check.

Signature

function pipe<T>(schema: Schema<T>, ...actions: Action<T>[]): Schema<T>

Parameters

Parameter	Type	Description
schema	Schema<T>	The base schema: string(), number(), array(...)…
actions	Action<T>[]	Rules and transforms

Execution order

1. The base schema is checked. On error the rules don't run.
2. Rules and transforms run left to right. Each one gets the result of the previous: pipe(string(), trim(), minLength(2)) checks the length of the trimmed string.
3. Execution stops at the first error. With the { all: true } option of validate all rules are checked.
4. Async rules (checkAsync) run last and only if the others passed.

What you can pass

Kind	Actions
Length	minLength, maxLength, length
Numbers	min, max, between, integer
Format	pattern, email, url, uuid, startsWith, endsWith, includes
Dates	minDate, maxDate, after, before
Arrays	unique
Checksums	inn, snils, luhn
Comparison	sameAs
Transforms	trim, toLowerCase, toUpperCase
Custom	check, checkAsync

TypeScript checks that a rule matches the schema type: pipe(string(), min(1)) is a compile error.

Transforms inside pipe keep the type. To get a value of another type, use transform.

Examples

Username

const username = pipe(
  string(),
  trim(),
  toLowerCase(),
  minLength(3),
  maxLength(20),
  pattern(/^[a-z0-9_]+$/, 'Only latin letters, digits and _'),
);

With optional

// optional goes outside pipe
const phone = optional(pipe(string(), pattern(/^\+1\d{10}$/)));

See also

• check — a custom rule
• transform — change the type
• validate — the all option