jest-bench
v29.7.1
Published
Run benchmark with Jest
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Jest-Bench
Run benchmark with Jest. Write benchmark files along with your test files, and benchmark using any existing test environment you're using. This package builds on top of the excellent benchmark package.
Which version to install
Some environments such as jest-electron
are only useable with Jest version less than 27, therefore this package takes its version after Jest version for easy installation:
| Jest version | Jest-Bench version | | ------------ | ------------------ | | 29.x.x | 29.x.x | | 28.x.x | 28.x.x | | 27.x.x | 27.x.x | | 26.x.x | 26.x.x |
For contributors, branch main
works with Jest version 29.
How to use
Install
npm i -D jest-bench
Create a jest config file just for running benchmarks. You can use names such as jest-bench.config.json
.
{
// Jest-bench need its own test environment to function
"testEnvironment": "jest-bench/environment",
"testEnvironmentOptions": {
// still Jest-bench environment will run your environment if you specify it here
"testEnvironment": "jest-environment-node",
"testEnvironmentOptions": {
// specify any option for your environment
}
},
// always include "default" reporter along with Jest-bench reporter
// for error reporting
"reporters": ["default", "jest-bench/reporter"],
// will pick up "*.bench.js" files or files in "__benchmarks__" folder.
"testRegex": "(/__benchmarks__/.*|\\.bench)\\.(ts|tsx|js)$",
...
}
You can optionally define some reporter options for extra control
{
...,
"reporters": ["default", ["jest-bench/reporter", {withOpsPerSecond: true}]],
...
}
Now any files with names that match *.bench.js
, or are inside __benchmarks__
folder will be considered benchmark files. More examples:
import { benchmarkSuite } from "jest-bench";
let a;
benchmarkSuite("sample", {
// setup will not run just once, it will run for each loop
setup() {
a = [...Array(10e6).keys()];
},
// same thing with teardown
teardown() {
if (a.length < 10e6) a.unshift(0);
},
["Array.indexOf"]: () => {
a.indexOf(555599);
},
["delete Array[i]"]: () => {
expect(a.length).toEqual(10e6);
delete a[0];
},
["Array.unshift"]: () => {
a.unshift(-1);
},
["Array.push"]: () => {
a.push(1000000);
},
["Async test"]: (deferred) => {
// Call deferred.resolve() at the end of the test.
new Promise((resolve) => setTimeout(resolve, 10)).then(() => deferred.resolve());
},
});
To see more examples, check out the test
folder. You can now run benchmarks like this:
npx jest --projects jest-bench.config.json
Jest-bench saves benchmark results to benchmarks/result.txt
in addition to being printed, so you might want to add this folder to .gitignore.
# .gitignore
benchmarks/result.txt
Reference
benchmarkSuite(name, description[, timeoutMsOrOptions])
Create and run a new suite. Each suite creates and is associated with a describe
block underneath.
- name: string, name of suite.
- description: object, an object with each key represents a single benchmark. Behind the scene, each benchmark runs in a
test
block. You can also write jest assertions, even though doing so makes little sense as it will affect benchmark results. Special keys include:- setup: run before each loop of benchmark. Note that this and
teardown
are evaled together with the benchmark. So once you declare this, any variable defined outside ofsetup
andteardown
becomes invisible to the benchmark. If this andteardown
are not defined then benchmarks will still be able to see variables in outer scopes. - teardown: run after each loop of benchmark. Note the caveat above.
- setupSuite: run once before all benchmarks. This block, in effect, is the same as a
beforeAll
block (and it does callbeforeAll
underneath). Again you probably don't want to define or initialize variables here if you also includesetup
orteardown
. - teardownSuite: run once after all benchmarks have concluded.
- setup: run before each loop of benchmark. Note that this and
- timeoutMsOrOptions:
- number of milliseconds before a benchmark timeouts. Default to 60000,
- or a
SuiteOptions
:delay
,initCount
,maxTime
,minSamples
,minTime
are passed to Benchmark. See the documentation for more info.timeoutSeconds
is the number of seconds before a benchmark timeouts. Default to 60.