Validating JSON Data

import ZSchema from 'z-schema';

const validator = ZSchema.create();

const schema = {
  type: 'object',
  properties: {
    name: { type: 'string' },
    age: { type: 'integer', minimum: 0 },
  },
  required: ['name'],
};

// Throws on invalid data
validator.validate({ name: 'Alice', age: 30 }, schema);

import ZSchema from 'z-schema';

const validator = ZSchema.create();

try {
  validator.validate(data, schema);
} catch (err) {
  // err is ValidateError
  console.log(err.details); // SchemaErrorDetail[]
}

const validator = ZSchema.create({ safe: true });

const result = validator.validate(data, schema);
if (!result.valid) {
  console.log(result.err?.details);
}

const validator = ZSchema.create();
const { valid, err } = validator.validateSafe(data, schema);

const validator = ZSchema.create({ async: true });

try {
  await validator.validate(data, schema);
} catch (err) {
  console.log(err.details);
}

const validator = ZSchema.create({ async: true, safe: true });

const { valid, err } = await validator.validate(data, schema);

interface SchemaErrorDetail {
  message: string; // "Expected type string but found type number"
  code: string; // "INVALID_TYPE"
  params: (string | number | Array<string | number>)[];
  path: string | Array<string | number>; // "#/age" or ["age"]
  keyword?: string; // "type", "required", "minLength", etc.
  inner?: SchemaErrorDetail[]; // sub-errors from anyOf/oneOf/not
  schemaPath?: Array<string | number>;
  schemaId?: string;
}

const { valid, err } = validator.validateSafe(data, schema);
if (!valid && err) {
  for (const detail of err.details) {
    console.log(`${detail.path}: [${detail.code}] ${detail.message}`);
    if (detail.inner) {
      for (const sub of detail.inner) {
        console.log(`  └─ ${sub.path}: [${sub.code}] ${sub.message}`);
      }
    }
  }
}

// Only report type errors
validator.validate(data, schema, { includeErrors: ['INVALID_TYPE'] });

// Suppress string-length errors
validator.validate(data, schema, { excludeErrors: ['MIN_LENGTH', 'MAX_LENGTH'] });

const validator = ZSchema.create();

const schemas = [
  {
    id: 'address',
    type: 'object',
    properties: { city: { type: 'string' }, zip: { type: 'string' } },
    required: ['city'],
  },
  {
    id: 'person',
    type: 'object',
    properties: {
      name: { type: 'string' },
      home: { $ref: 'address' },
    },
    required: ['name'],
  },
];

// Compile all schemas (validates them and registers references)
validator.validateSchema(schemas);

// Validate data using a compiled schema ID
validator.validate({ name: 'Alice', home: { city: 'Paris' } }, 'person');

ZSchema.setRemoteReference('http://example.com/schemas/address.json', addressSchema);
// or per-instance:
validator.setRemoteReference('http://example.com/schemas/person.json', personSchema);

import fs from 'node:fs';
import path from 'node:path';

ZSchema.setSchemaReader((uri) => {
  const filePath = path.resolve(__dirname, 'schemas', uri + '.json');
  return JSON.parse(fs.readFileSync(filePath, 'utf8'));
});

const { valid, err } = validator.validateSafe(data, schema);
if (!valid && err) {
  const missing = validator.getMissingReferences(err);
  const remote = validator.getMissingRemoteReferences(err);
}

ZSchema.registerFormat('postal-code', (value) => {
  return typeof value === 'string' && /^\d{5}(-\d{4})?$/.test(value);
});

const validator = ZSchema.create();
validator.registerFormat('postal-code', (value) => {
  return typeof value === 'string' && /^\d{5}(-\d{4})?$/.test(value);
});

const validator = ZSchema.create({
  customFormats: {
    'postal-code': (value) => typeof value === 'string' && /^\d{5}(-\d{4})?$/.test(value),
  },
});

const validator = ZSchema.create({ async: true });
validator.registerFormat('user-exists', async (value) => {
  if (typeof value !== 'number') return false;
  const user = await db.findUser(value);
  return user != null;
});

const formats = ZSchema.getRegisteredFormats();

const validator = ZSchema.create({ version: 'draft-07' });