Arrays

w.array() creates schemas for arrays with typed items.

Basic Usage

Pass the item schema to w.array():

const names = w.array(w.string());
// string[]

const numbers = w.array(w.integer().min(0));
// number[]

Length Constraints

w.array(w.string()).minItems(1)      // At least 1 item
w.array(w.string()).maxItems(10)     // At most 10 items
w.array(w.string()).length(3)        // Exactly 3 items
w.array(w.string()).nonEmpty()       // Shorthand for minItems(1)

Nested Objects

Arrays can contain any schema type:

const lineItems = w.array(
  w.object({
    description: w.string().minLen(1),
    amount: w.money().nonNegative(),
    quantity: w.integer().positive(),
  })
).nonEmpty();

Nested Arrays

const matrix = w.array(w.array(w.number()));
// number[][]

Type Inference

import type { Infer } from "wellformed-ts";

const schema = w.array(
  w.object({
    name: w.string(),
    score: w.number(),
  })
);

type T = Infer<typeof schema>;
// { name: string; score: number }[]

Validation

Each item in the array is validated against the item schema. Errors include the item index in the path:

import { validate } from "wellformed-ts";

const schema = w.array(w.string().minLen(1)).toSchema("1.0");
const result = validate(schema, ["hello", ""]);

console.log(result.errors);
// [{ path: "/1", code: "TOO_SHORT", message: "Must be at least 1 characters" }]