@zap-studio/validation

Standard Schema utilities and ValidationError helpers.

Why @zap-studio/validation?

When working with Standard Schema-compatible libraries (Zod, Valibot, ArkType, etc.), you often want:

• A single error type to represent validation failures.
• A simple way to detect whether a value is a Standard Schema.
• A consistent helper for validating data in both throwing and non-throwing modes.

@zap-studio/validation provides exactly that, and is used internally by @zap-studio/fetch and other Zap Studio runtime packages.

Installation

pnpm add @zap-studio/validation
# or
npm install @zap-studio/validation

Core Concepts

ValidationError

ValidationError is a shared error type thrown when Standard Schema validation fails.

import { ValidationError } from "@zap-studio/validation/errors";

try {
  const value = await standardValidate(schema, data, true);
  console.log("Validated:", value);
} catch (error) {
  if (error instanceof ValidationError) {
    console.error("Validation failed:", error.issues);
  }
}

isStandardSchema

isStandardSchema is a type guard that tells you whether a value is a Standard Schema-compatible schema.

import { isStandardSchema } from "@zap-studio/validation";

if (isStandardSchema(schema)) {
  // TypeScript now knows `schema` is a StandardSchemaV1
  const result = await standardValidate(schema, data, true);
}

standardValidate

standardValidate normalizes sync and async Standard Schema validation, and supports both throwing and non-throwing flows.

import { standardValidate } from "@zap-studio/validation";

// Synchronous or asynchronous schema – handled transparently
const value = await standardValidate(schema, data, true);

// Non-throwing mode (sync or async schema)
const result = await standardValidate(schema, data, false);
if (result.issues) {
  console.error("Validation failed:", result.issues);
} else {
  console.log("Validation passed:", result.value);
}

createSyncStandardValidator

createSyncStandardValidator builds a synchronous validator function from a Standard Schema schema. It calls schema["~standard"].validate and throws if the schema performs async validation (returns a Promise).

import { createSyncStandardValidator } from "@zap-studio/validation";

// Build a sync-only validator for a Standard Schema-compatible schema
const validateUser = createSyncStandardValidator(UserSchema);

const result = validateUser(data);
if (result.issues) {
  console.error("Validation failed:", result.issues);
} else {
  console.log("Validation passed:", result.value);
}