Error encountered: The function performance.now() cannot be executed because performance is undefined

Question

Error encountered: The function performance.now() cannot be executed because performance is undefined

I'm encountering a problem with the error

ReferenceError: performance is not defined

while attempting to use performance.now() for measuring the execution time of a function call:

export async function find(someId: string, ctx: context.IContext) {

      try {
        var t0 = performance.now();

        var res = someModel.find(someId, ctx.cookies);

        var t1 = performance.now();
        console.log("Call to find took " + (t1 - t0) + " milliseconds.");

        return res;
      } catch (err) {
        console.error(err);
        throw err;
      }
    }

Can anyone provide suggestions on how I could resolve this issue?

javascript typescript frontend performance.now

Answer 1

Answer №1

Although this question is tagged front-end, for those seeking a node.js solution (such as myself), remember to import the performance module from perf_hooks (which is included in node version 8.5 and above).

const {performance} = require('perf_hooks');
const t0 = performance.now();
...

Answer 2

Although this question is tagged front-end, for those seeking a node.js solution (such as myself), remember to import the performance module from perf_hooks (which is included in node version 8.5 and above).

const {performance} = require('perf_hooks');
const t0 = performance.now();
...

Answer 3

Answer №2

When working with the 'perf_hook' module, it is essential to specify which construct you intend to use since it exports various entities like objects, functions, and constants. Specifically, you will require the performance construct. There are two ways to declare this:

const performance = require('perf_hooks').performance;

Alternatively,

const { performance } = require('perf_hooks'); //utilizing object destructuring

Answer 4

When working with the 'perf_hook' module, it is essential to specify which construct you intend to use since it exports various entities like objects, functions, and constants. Specifically, you will require the performance construct. There are two ways to declare this:

const performance = require('perf_hooks').performance;

Alternatively,

const { performance } = require('perf_hooks'); //utilizing object destructuring

Answer 5

Answer №3

If you want to maintain type information, it's recommended to use the import statement instead of require when importing "performance" in TypeScript:

import {performance, PerformanceObserver} from 'perf_hooks';

const observer = new PerformanceObserver(items => items.getEntries().forEach((entry) => console.log(entry)));    
observer.observe({entryTypes: ['measure']});

performance.mark('start');
performance.mark('stop');
performance.measure('Measurement', 'start', 'stop');

Don't forget to include @types/node in your "dependencies" section of your "package.json" file.

This code has been tested with TypeScript 4 and Node.js 14.

Answer 6

If you want to maintain type information, it's recommended to use the import statement instead of require when importing "performance" in TypeScript:

import {performance, PerformanceObserver} from 'perf_hooks';

const observer = new PerformanceObserver(items => items.getEntries().forEach((entry) => console.log(entry)));    
observer.observe({entryTypes: ['measure']});

performance.mark('start');
performance.mark('stop');
performance.measure('Measurement', 'start', 'stop');

Don't forget to include @types/node in your "dependencies" section of your "package.json" file.

This code has been tested with TypeScript 4 and Node.js 14.

Answer 7

Answer №4

Absolutely! Just like the responses above, you'll need to include this snippet of code:

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

However, you can also execute performance.now() directly within your browser console or by navigating to the browser's source tab and selecting snippet without having to add the code mentioned previously.

To delve deeper into this topic, feel free to check out the following link:

https://nodejs.org/api/perf_hooks.html#perf_hooks_performance_now

Answer 8

Absolutely! Just like the responses above, you'll need to include this snippet of code:

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

However, you can also execute performance.now() directly within your browser console or by navigating to the browser's source tab and selecting snippet without having to add the code mentioned previously.

To delve deeper into this topic, feel free to check out the following link:

https://nodejs.org/api/perf_hooks.html#perf_hooks_performance_now

Answer 9

Answer №5

My experience was on a brand new next.js project, just after completing the installation wizard and integrating apollo. The issue was resolved by updating NODE to the most recent version.

You can achieve this by using nvm use 18 or by including a .nvmrc file in your application.

Answer 10

My experience was on a brand new next.js project, just after completing the installation wizard and integrating apollo. The issue was resolved by updating NODE to the most recent version.

You can achieve this by using nvm use 18 or by including a .nvmrc file in your application.

Error encountered: The function performance.now() cannot be executed because performance is undefined

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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