What are some examples of performance testing with Jest?

What are some examples of performance testing with Jest?

Jest is primarily a testing framework for JavaScript, but you can use it for performance testing by measuring execution time. For example, you can use performance.now() to track how long a function takes to execute.

Can you show me a code snippet for that?

Sure! Here's a simple example:

const { performance } = require('perf_hooks');

function myFunction() {
    // Simulate some work
    for (let i = 0; i < 1e6; i++) {} 
}

const start = performance.now();
myFunction();
const end = performance.now();
console.log(`Execution time: ${end - start} milliseconds`);

How can I integrate this with my Jest tests?

You can integrate it by using Jest's test function. Here's how:

test('myFunction performance', () => {
    const start = performance.now();
    myFunction();
    const end = performance.now();
    expect(end - start).toBeLessThan(100); // Example threshold
});