Category: JavaScript

Sometimes, we want to reload the page with hash value with JavaScript.

In this article, we’ll look at how to reload the page with hash value with JavaScript.

How to reload the page with hash value with JavaScript?

To reload the page with hash value with JavaScript, we can set the window.location.hash property to the hash string.

Then we reload the page.

For instance, we write

window.location.hash = "#mypara";
location.reload();

to set window.location.hash to the hash string to append it to the end of the URL.

Then we call location.reload to reload the page.

Conclusion

To reload the page with hash value with JavaScript, we can set the window.location.hash property to the hash string.

Sometimes, we want to capture the close event of popup window in JavaScript.

In this article, we’ll look at how to capture the close event of popup window in JavaScript.

How to capture the close event of popup window in JavaScript?

To capture the close event of popup window in JavaScript, we can watch for the window to close with a timer.

For instance, we write

const win = window.open("https://www.example.com");

const timer = setInterval(() => {
  if (win.closed) {
    clearInterval(timer);
    console.log("closed");
  }
}, 1000);

to call window.open to open a popup with the URL.

Then we call setInterval with a callback that checks if the popup is closed with win.closed every second.

If it’s true, then we call clearInterval with timer to stop the setInterval timer.

Conclusion

To capture the close event of popup window in JavaScript, we can watch for the window to close with a timer.

Sometimes, we want to check if token expired using this JWT library with JavaScript.

In this article, we’ll look at how to check if token expired using this JWT library with JavaScript.

How to check if token expired using this JWT library with JavaScript?

To check if token expired using this JWT library with JavaScript, we use the jwt.verify method.

For instance, we write

const jwt = require("jsonwebtoken");

const decoded = jwt.verify(token, secret);

to call jwt.verify with token and secret to verify the JWT token string against the secret string.

It’ll also check if token has expired.

Conclusion

To check if token expired using this JWT library with JavaScript, we use the jwt.verify method.

Sometimes, we want to perform a global replace on string with a variable inside ‘/’ and ‘/g’ in JavaScript.

In this article, we’ll look at how to perform a global replace on string with a variable inside ‘/’ and ‘/g’ in JavaScript.

How to perform a global replace on string with a variable inside ‘/’ and ‘/g’ in JavaScript?

To perform a global replace on string with a variable inside ‘/’ and ‘/g’ in JavaScript, we can use the RegExp constructor.

For instance, we write

const myString = "hello world test world";
const find = "world";
const regex = new RegExp(find, "g");
console.log(myString.replace(regex, "yay"));

to create a regex that matches all instances of the find string by calling it with find and 'g'.

Then we call myString.replace with regex and 'yay' to replace all instances of 'world' with 'yay'.

Conclusion

To perform a global replace on string with a variable inside ‘/’ and ‘/g’ in JavaScript, we can use the RegExp constructor.

Sometimes, we want to mock globals in Jest and JavaScript.

In this article, we’ll look at how to mock globals in Jest and JavaScript.

How to mock globals in Jest and JavaScript?

To mock globals in Jest and JavaScript, we can use the spyOn and mockImplementation methods.

For instance, in the beforeAll callback, we write

jest.spyOn(window, "navigator", "get").mockImplementation(() => {
  //...
});

to call spyOn to create a mock for the window.navigator.get method.

And then we call mockImplemenetation on the returned mocked object with a callback with the mocked implementation of window.navigator.get.

Then in the afterAll callback, we write

jest.restoreAllMocks();

to clear all the mocks.

Conclusion

To mock globals in Jest and JavaScript, we can use the spyOn and mockImplementation methods.