How to measure the execution time of a promise?

by

If the functions you want to measure will always be synchronous there’s really no need to involve promises.

Since the function you want to test takes parameters you it’s best to to wrap it in an arrow function in order to be able to call it with another context and not have to manage it’s parameters yourself.

Something simple like this will do just fine.

function measure(fn: () => void): number {
    let start = performance.now();
    fn();
    return performance.now() - start;
}

function longRunningFunction(n: number) {
    for (let i = 0; i < n; i++) {
        console.log(i);
    }
}

let duration = measure(() => {
    longRunningFunction(100);
});

console.log(`took ${duration} ms`);

If you want to measure the time it takes an async function (if it returns a promise) to resolve you can easily change the code to something like this:

function measurePromise(fn: () => Promise<any>): Promise<number> {
    let onPromiseDone = () => performance.now() - start;

    let start = performance.now();
    return fn().then(onPromiseDone, onPromiseDone);
}

function longPromise(delay: number) {
    return new Promise<string>((resolve) => {
        setTimeout(() => {
            resolve('Done');
        }, delay);
    });
}

measurePromise(() => longPromise(300))
    .then((duration) => {
        console.log(`promise took ${duration} ms`);
    });

Note: This solution uses the ES6 Promise, if you are using something else you might have to adapt it but the logic should be the same.

You can see both examples working in the playground here.

More Related Contents:

  1. How to use Typescript with native ES6 Promises
  2. typescript anonymous object with variable based label value
  3. Can’t bind to ‘ngModel’ since it isn’t a known property of ‘input’
  4. Cancel a vanilla ECMAScript 6 Promise chain
  5. Angular 2: How to detect changes in an array? (@input property)
  6. Dynamically loading a typescript class (reflection for typescript)
  7. Why duck typing is allowed for classes in TypeScript
  8. What is the best way to limit concurrency when using ES6’s Promise.all()?
  9. Typescript compile to single file
  10. Catch all unhandled javascript promise rejections
  11. using a fetch inside another fetch in javascript
  12. How to reuse existing C# class definitions in TypeScript projects
  13. Vuejs typescript this.$refs..value does not exist
  14. Is it a good practice using Observable with async/await?
  15. How to parse JSON string in Typescript
  16. `this` is undefined in Dev Tools when using arrow function
  17. Promise.all with Firebase DataSnapshot.forEach
  18. ES6 Promise not Updating AngularJS DOM [duplicate]
  19. Why does the Promise constructor require a function that calls ‘resolve’ when complete, but ‘then’ does not – it returns a value instead?
  20. Angular 2 Component @Input not working
  21. Highlight the search text – angular 2
  22. angular 4+ assign @Input for ngComponentOutlet dynamically created component
  23. How to loop over object properties with ngFor in Angular
  24. Converting an image to base64 in angular 2
  25. Typescript Promise rejection type
  26. How can I get the Typescript compiler to output the compiled js to a different directory?
  27. How to check empty object in angular 2 template using *ngIf
  28. Browser Detection in ReactJS
  29. When is the body of a Promise constructor callback executed?
  30. Next.js app folder: is there some “entry point”? A direct replacement for _app.tsx?

Leave a Comment