Thunder Client Guide: How to Use the `tc` Object in Scripting

Looking to up your API testing game? Thunder Client holds a powerful secret in its scripting capabilities, available in its paid version. Let’s break down how to use the tc object for various advanced use cases, making your API testing smooth and efficient.

Introduction to Thunder Client

Thunder Client is a lightweight REST API client for Visual Studio Code, designed to simplify API testing. It allows you to set environment variables, extract data from responses, execute test assertions, and more. For these advanced tasks, the scripting feature in the paid version is indispensable.

Using the tc Object in Scripting

Global Variables

The tc object is your primary hub for API access in Thunder Client. Alongside tc, you also get access to other useful global variables like expect and assert from the Chai assertion library, and functions like btoa for Base64 encoding and atob for Base64 decoding.

Built-in Libraries

Thunder Client provides several built-in libraries for various tasks:

• axios: Promise-based HTTP client
• chai: Assertion library
• crypto-js: Cryptographic operations
• fs: File system module
• http/https: HTTP and HTTPS modules
• uuid: UUID generator

Using axios

const axios = require('axios');
const response = await axios.get("https://www.thunderclient.com/welcome");
console.log(response);

Managing Requests

Request Object

You can access and modify the request object properties:

• tc.request.id
• tc.request.url
• tc.request.method
• tc.request.headers
• tc.request.body

Modifying Headers

tc.request.setHeader('Content-Type', 'application/json');
const contentType = tc.request.getHeader('Content-Type');
console.log(contentType);

Modifying Body

tc.request.setBody({ key: "value" });
console.log(tc.request.body);

Managing Responses

Response Object

This object is read-only and contains properties like:

• tc.response.status
• tc.response.time
• tc.response.contentType
• tc.response.json
• tc.response.text

Accessing Headers and Cookies

const responseHeader = tc.response.getHeader('Set-Cookie');
console.log(responseHeader);

const binaryResponse = tc.response.getBinary();
console.log(binaryResponse);

Advanced Methods

Handling Variables

tc.setVar('myVar', 'value');
const myVar = tc.getVar('myVar');
console.log(myVar);

Running and Retrying Requests

await tc.runRequest('reqId');

await tc.retryRequest();

Skipping Requests

tc.skipRequest('reqId');

Why EchoAPI is a Great Alternative

If you’re considering alternatives, EchoAPI for VS Code is a powerful, ultra-lightweight collaboration tool perfect for API development. It supports features like API design, debugging, automated testing, load testing, and more.

Key Features of EchoAPI:

1. No login required: Start immediately without the hassle of signing up.
2. Supports Scratch Pad: Quickly jot down notes or temporary code.
3. Ultra lightweight: Designed to be fast and efficient.
4. 100% compatible with Postman script syntax: Easily migrate or use your existing scripts.

EchoAPI seamlessly integrates with IntelliJ IDEA, VS Code, and Chrome request capture extension, enhancing your API development workflow significantly.

By leveraging the full power of the tc object, you can perform highly efficient and advanced API testing with Thunder Client. Whether you stick with Thunder Client or try out EchoAPI, both tools offer robust features to streamline your API workflows. Happy testing!