Problem: Build a Vendor-Agnostic API Client Factory

Easy

15 min

Return different API clients (REST, GraphQL, SOAP) based on a config value, without switch logic.

Problem statement

You’re integrating with multiple third-party APIs. Depending on the config, your app needs to use either a REST, GraphQL, or SOAP client implementation. You want to hide this complexity behind a factory that takes a string, type, and returns the corresponding client. The system should remain open to adding more client types in the future, without requiring edits to multiple places.

Goal

Implement createApiClient(type) that returns an instance of RestClient, GraphQLClient, or SoapClient, based on the type string passed.

Constraints

Do not use conditionals (if, switch, ternaries) to select which class to instantiate.
Only the factory knows how to select and instantiate the client.
Assume only those 3 client types exist for now.

Sample output

The examples below illustrate what the output should look like:

Problem: Build a Vendor-Agnostic API Client Factory

Easy

15 min

Return different API clients (REST, GraphQL, SOAP) based on a config value, without switch logic.

Problem statement

Goal

Implement createApiClient(type) that returns an instance of RestClient, GraphQLClient, or SoapClient, based on the type string passed.

Constraints

Do not use conditionals (if, switch, ternaries) to select which class to instantiate.
Only the factory knows how to select and instantiate the client.
Assume only those 3 client types exist for now.

Sample output

The examples below illustrate what the output should look like:

Similar Problems

Build a Multi-Tenant Service Factory

Factory for Dynamically Composed Middleware Chains

Create an Environment-Specific Database Client Factory

Add Feature-Flagged Logger Instantiation

Implement a Config-Driven Notification Service Factory

Dynamically Load a Database Client Using ES Modules

Create a Pluggable Payment Processor Factory

Create a Feature-Flagged Analytics Service

Node.js

class RestClient {
  fetch(endpoint) {
    return `REST fetching ${endpoint}`;
  }
}
class GraphQLClient {
  fetch(endpoint) {
    return `GraphQL querying ${endpoint}`;
  }
}
class SoapClient {
  fetch(endpoint) {
    return `SOAP invoking ${endpoint}`;
  }
}
// Implement this
function createApiClient(type) {
  // return appropriate client instance
}
// Example usage
const graphqlClient = createApiClient('graphql');
console.log(graphqlClient.fetch('/users'));
/* Expected output:
GraphQL querying /users */
const restClient = createApiClient('rest');
console.log(restClient.fetch('/posts'));
/* Expected output:
REST fetching /posts */
const soapClient = createApiClient('soap');
console.log(soapClient.fetch('/orders'));
/* Expected output:
SOAP invoking /orders */