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Touca SDK for JavaScript - v1.5.3

Touca SDK for JavaScript

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Touca helps you understand the true impact of your day to day code changes on the behavior and performance of your overall software, as you write code.

Touca Server

Touca SDKs let you describe the behavior and performance of your code by capturing values of interesting variables and runtime of important functions. We remotely compare your description against a trusted version of your software, visualize all differences, and report them in near real-time.

🧑‍🔧 Install

You can install Touca with NPM:

npm install @touca/node

We formally support Node.js v12 and newer on Windows, Linux and macOS platforms.

👀 Sneak Peak

For a more thorough guide of how to use Touca SDK for JavaScript, check out the examples directory or visit our documentation website.

Let us imagine that we want to test a software workflow that reports whether a given number is prime.

function is_prime(input: number): boolean;

We can use unit testing in which we hard-code a set of input numbers and list our expected return value for each input. In this example, the input and output of our code under test are a number and a boolean. If we were testing a video compression algorithm, they may have been video files. In that case:

  • Describing the expected output for a given video file would be difficult.

  • When we make changes to our compression algorithm, accurately reflecting those changes in our expected values would be time-consuming.

  • We would need a large number of input video files to gain confidence that our algorithm works correctly.

Touca makes it easier to continuously test workflows of any complexity and with any number of test cases.

import { touca } from '@touca/node';
import { is_prime } from './code_under_test';

touca.workflow('is_prime_test', (testcase: string) => {
const number = Number.parseInt(testcase);
touca.check('is_prime_output', is_prime(number));


Touca tests have two main differences compared to typical unit tests:

  • We have fully decoupled our test inputs from our test logic. We refer to these inputs as "test cases". The SDK retrieves the test cases from the command line, or a file, or a remote Touca server and feeds them one by one to our code under test.

  • We have removed the concept of expected values. With Touca, we only describe the actual behavior and performance of our code under test by capturing values of interesting variables and runtime of important functions, anywhere within our code. For each test case, the SDK submits this description to a remote server which compares it against the description for a trusted version of our code. The server visualizes any differences and reports them in near real-time.

We can run Touca tests with any number of inputs from the command line:

node dist/is_prime_test.js --revision v1.0 --testcase 13 17 51

Where TOUCA_API_KEY and TOUCA_API_URL can be obtained from the Touca server at app.touca.io. This command produces the following output:

Touca Test Framework
Suite: is_prime_test/v1.0

 1.  PASS   13    (109 ms)
 2.  PASS   17    (152 ms)
 3.  PASS   51    (127 ms)

Tests:      3 passed, 3 total
Time:       0.91 s

✨   Ran all test suites.

✨ Features

Touca is very effective in addressing common problems in the following situations:

  • When we need to test our workflow with a large number of inputs.

  • When the output of our workflow is too complex, or too difficult to describe in our unit tests.

  • When interesting information to check for regression is not exposed through the interface of our workflow.

The fundamental design features of Touca that we highlighted earlier can help us test these workflows at any scale.

  • Decoupling our test input from our test logic, can help us manage our long list of inputs without modifying the test logic. Managing that list on a remote server accessible to all members of our team, can help us add notes to each test case, explain why they are needed and track how their performance changes over time.

  • Submitting our test results to a remote server, instead of storing them in files, can help us avoid the mundane tasks of managing and processing of those results. The Touca server retains test results and makes them accessible to all members of the team. It compares test results using their original data types and reports discovered differences in real-time to all interested members of our team. It allows us to audit how our software evolves over time and provides high-level information about our tests.

📖 Documentation

🙋 Ask for Help

We want Touca to work well for you. If you need help, have any questions, or like to provide feedback, send us a note through the Intercom at app.touca.io or email us at hello@touca.io.


This repository is released under the Apache-2.0 License. See LICENSE.