Function validate

Example

import { validate } from '@aws-lambda-powertools/validation';

const schema = {
  type: 'object',
  properties: {
    name: { type: 'string' },
    age: { type: 'number' },
  },
  required: ['name', 'age'],
  additionalProperties: false,
} as const;

const payload = { name: 'John', age: 30 };

const validatedData = validate({
  payload,
  schema,
});
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When validating, you can also provide an optional JMESPath expression to extract a specific part of the payload before validation using the envelope parameter. This is useful when the payload is nested or when you want to validate only a specific part of it.

import { validate } from '@aws-lambda-powertools/validation';

const schema = {
  type: 'object',
  properties: {
    user: { type: 'string' },
  },
  required: ['user'],
  additionalProperties: false,
} as const;

const payload = {
  data: {
    user: 'Alice',
  },
};

const validatedData = validate({
  payload,
  schema,
  envelope: 'data',
});
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Since the Validation utility is built on top of Ajv, you can also provide custom formats and external references to the validation process. This allows you to extend the validation capabilities of Ajv to suit your specific needs.

Example

import { validate } from '@aws-lambda-powertools/validation';

const formats = {
  ageRange: (value: number) => return value >= 0 && value <= 120,
};

const definitionSchema = {
  $id: 'https://example.com/schemas/definitions.json',
  definitions: {
    user: {
      type: 'object',
      properties: {
        name: { type: 'string' },
        age: { type: 'number', format: 'ageRange' },
      },
      required: ['name', 'age'],
      additionalProperties: false,
    }
  }
} as const;

const schema = {
  $id: 'https://example.com/schemas/user.json',
  type: 'object',
  properties: {
    user: { $ref: 'definitions.json#/definitions/user' },
  },
  required: ['user'],
  additionalProperties: false,
} as const;

const payload = {
  user: {
    name: 'Alice',
    age: 25,
  },
};

const validatedData = validate({
  payload,
  schema,
  externalRefs: [definitionSchema],
  formats,
});
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Additionally, you can provide an existing Ajv instance to reuse the same instance across multiple validations. If you don't provide an Ajv instance, a new one will be created for each validation.