NodeJS + TypeScript Error TS2339: Property 'timeOrigin' does not exist on type 'Performance' - node.js

Question

I have a NodeJS/TypeScript app that uses Selenium WebDriver, which has approximately this snippet:
import { WebDriver } from "selenium-webdriver";
export class MyClass {
public async getTimeOrigin(driver: WebDriver): Promise<number> {
return await driver.executeScript(function () {
// This should be the DOM's timeOrigin (same as if a person types "performance.timeOrigin"
// into the Chrome DevTools console)
return performance.timeOrigin;
});
}
}
When I attempt to build the above, I get the following error message:
error TS2339: Property 'timeOrigin' does not exist on type 'Performance'
But it does certainly exist, since I can looks up the references on the Performance object and see timeOrigin inside. Can anyone please advise on how to fix this and correctly access the timeOrigin property?

Answer 1

performance is a global variable which is only available to the web browser you test. While you're working in NodeJS environment, it doesn't have any global performance, that's why Typescript cannot detect it and throw the error when compiling.
To fix this, you only need a simple global variable declaration:
declare var performance: any;
If you're using a lot of web interfaces in your Node environment, I recommend you import the lib lib.dom to typescript to avoid these types of errors:
{
"compilerOptions": {
"lib": [
"dom"
]
}
}
As mentioned by mcernak, another way is to use string as input to executeScript function.

Answer 2

To avoid the compilation issues, you can provide the script that you want to execute in context of the browser as a string(instead of a function):
public async getTimeOrigin(driver: WebDriver): Promise<number> {
return await driver.executeScript("return performance.timeOrigin;");
}
From the documentation of WebDriver.executeScript:
Executes a snippet of JavaScript in the context of the currently
selected frame or window. The script fragment will be executed as the
body of an anonymous function. If the script is provided as a function
object, that function will be converted to a string for injection into
the target window.

Answer 3

Maybe you can try to cast it as Performance.
import { WebDriver } from "selenium-webdriver";
export class MyClass {
public async getTimeOrigin(driver: WebDriver): Promise<number> {
return await driver.executeScript(function () {
// This should be the DOM's timeOrigin (same as if a person types "performance.timeOrigin"
// into the Chrome DevTools console)
const perf = <Performance>performance; // or "performance as Performance"
return perf.timeOrigin;
});
}
}