Compose Utilities

Purpose

The compose utilities provide functional combinators for working with validation results and schemas. mergeResults aggregates multiple ParseResult<T> values into a single ParseResult<T[]>, collecting all issues from failures. pipe composes a schema with one or more transform functions into a new pipeline schema, enabling clean left-to-right data transformation chains without manual wrapping.

Features

mergeResults<T>(results) — aggregate array of results, collecting all failures
pipe<T, U>(schema, ...transforms) — compose schema with sequential transforms

Usage: Basic Example

import { pipe, string } from "@suaveplan/validation";

const trimmedLength = pipe(
  string(),
  (v: unknown) => (v as string).trim(),
  (v: unknown) => (v as string).length,
);
trimmedLength.parse("  hello  "); // 5

Usage: Advanced Example

import { mergeResults, number } from "@suaveplan/validation";

const n = number().min(0);
const results = [1, 2, -3, 4].map((v) => n.safeParse(v));
const merged = mergeResults(results);
// merged.success === false, merged.error.issues has one issue for -3

API Reference

`mergeResults<T>(results: ParseResult<T>[]): ParseResult<T[]>`

If all results are successes, returns { success: true, data: T[] }. If any result is a failure, returns { success: false, error: ValidationError } with all issues aggregated from all failures.

`pipe<T, U>(schema: BaseSchema<unknown, T>, ...transforms: TransformFn<unknown, unknown>[]): BaseSchema<unknown, U>`

Chains schema with each transform in order using TransformSchema. Each transform receives the previous stage's output as unknown (type-cast by the caller). Returns a new schema producing type U.

Implementation Notes

mergeResults with an empty array returns { success: true, data: [] }.
pipe with no transforms returns the original schema (zero iterations of the loop).
Transform functions in pipe accept unknown to avoid TypeScript variance issues across the chain; callers must cast appropriately.

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