Introduction

This package provides a simple way to handle exceptions in your application. It is based on the Zod library, which is a TypeScript-first schema declaration and validation library.

Installation

yarn add @aircall/exception-zod

How to use

import { Exception } from '@aircall/exception';
import { zodMiddleware } from '@aircall/exception-zod';

// Let's say you have a function which creates a user
// First you define a schema to validate the body of the request
const schema = z.object({
  name: z.string().min(1),
  email: z.string().email(),
  age: z.number().int().positive()
});

// Let's say you have a lambda handler
export const handler = zodMiddleware(async (event: any) => {
  // You can use the `parse` method to validate the body of the request
  const body = schema.parse(event.body);

  // You can then use the `body` object to create a user
  const user = await createUser(body);

  return {
    statusCode: 200,
    body: JSON.stringify(user)
  };
});

// If the body of the request is invalid, the middleware will throw an exception
// You can catch the exception and return a proper response
try {
  const response = await handler(event);
} catch (error) {
  if (error instanceof Exception) {
    // Manage the exception however you want here
  }

  return {
    statusCode: 400,
    body: JSON.stringify({
      message: error.message
    })
  };
}

REST Integration

You can use the zodMiddleware also side restMiddleware which would automatically parse the body of the request and validate it against a schema. If the body is invalid, the middleware will throw an already formatted REST error using Aircall conventions.

import { restMiddleware } from '@aircall/exception-rest';
import { zodMiddleware } from '@aircall/exception-zod';

const schema = z.object({
  name: z.string().min(1),
  email: z.string().email(),
  age: z.number().int().positive()
});

export const handler = restMiddleware(
  zodMiddleware(async (event: any) => {
    // You can use the `parse` method to validate the body of the request
    // If the body is invalid, the zod will throw an exception
    // That will be caught by zodMiddleware to convert them to Aircall errors
    // And then by the restMiddleware to convert them to REST responses
    const body = schema.parse(event.body);

    const user = await createUser(body);

    return {
      statusCode: 200,
      body: JSON.stringify(user)
    };
  })
);

// Example of a request
const event = {
  body: JSON.stringify({
    name: 'J',
    email: 'abc',
    age: 1.2
  })
};

const response = await handler(event);

// response
{
  statusCode: 400,
  body: JSON.stringify({
    name: 'UserInputException',
    message: 'Invalid user input',
    code: '0100',
    issues: [
      {
        code: '0103',
        message: 'Input in "name" is too small, minimum is "1" "string"',
        minimum: 1,
        name: 'TooSmallException',
        path: 'name',
        type: 'string'
      },
      {
        name: 'InvalidStringException',
        message: 'Input in "email" has failed the "email" validation',
        code: '0102',
        path: 'email',
        validation: 'email'
      },
      {
        name: 'InvalidTypeException',
        code: '0101',
        expected: 'integer',
        message: 'Input in "age" expected to be "integer" but received "float"',
        path: 'age',
        received: 'float'
      }
    ]
  })
}

GraphQL Integration

You can use the zodMiddleware also side graphqlMiddleware which would automatically parse the body of the request and validate it against a schema. If the body is invalid, the middleware will throw an already formatted GraphQL error using Aircall conventions.

import { graphqlMiddleware } from '@aircall/exception-graphql';
import { zodMiddleware } from '@aircall/exception-zod';

const schema = z.object({
  name: z.string().min(1),
  email: z.string().email(),
  age: z.number().int().positive()
});

export const handler = graphqlMiddleware(
  zodMiddleware(async (event: any) => {
    // You can use the `parse` method to validate the body of the request
    // If the body is invalid, the zod will throw an exception
    // That will be caught by zodMiddleware to convert them to Aircall errors
    // And then by the graphqlMiddleware to convert them to GraphQL errors
    const body = schema.parse(event.body);

    const user = await createUser(body);

    return {
      user,
      __typename: 'User'
    };
  })
);

// Example of a request

const event = {
  body: JSON.stringify({
    query: `
      mutation {
        createUser(input: { name: "J", email: "abc", age: 1.2 }) {
          __typename

          ... on User {
            id
            name
            email
            age
          }

          ... on UserInputException {
            message

            issues {
              __typename
              message
              code
              path

              ... on TooSmallException {
                minimum
                type
              }

              ... on InvalidStringException {
                validation
              }

              ... on InvalidTypeException {
                received
                expected
              }
            }
          }
        }
      }
    `
  })
};

const response = await handler(event);

// response
{
  data: {
    __typename: 'UserInputException',
    message: 'Invalid user input',
    extensions: {
      code: '0100',
      issues: [
        {
          __typename: 'TooSmallException',
          code: '0103',
          message: 'Input in "name" is too small, minimum is "1" "string"',
          minimum: 1,
          path: 'name',
          type: 'string'
        },
        {
          __typename: 'InvalidStringException',
          code: '0102',
          message: 'Input in "email" has failed the "email" validation',
          path: 'email',
          validation: 'email'
        },
        {
          __typename: 'InvalidTypeException',
          code: '0101',
          message: 'Input in "age" expected to be "integer" but received "float"',
          path: 'age',
          expected: 'integer',
          received: 'float'
        }
      ]
    }
  }
}