Web developer specializing in React, Vue, and front end development.
Sometimes, we want to check for not null with JavaScript.
In this article, we’ll look at how to check for not null with JavaScript.
To check for not null with JavaScript, we can use the !== operator.
For instance, we write
if (val !== null) {
//...
}
to check if val isn’t equal to null with
val !== null
To check for not null with JavaScript, we can use the !== operator.
Sometimes, we want to remove padding or margins from Google Charts and JavaScript.
In this article, we’ll look at how to remove padding or margins from Google Charts and JavaScript.
To remove padding or margins from Google Charts and JavaScript, we can set the width and height options.
For instance, we write
const options = {
title: "How Much I Ate Last Night",
width: 350,
height: 400,
chartArea: { width: "100%", height: "80%" },
legend: { position: "bottom" },
};
to set the width and height in pixels.
And then we set the chartArea to fill 100% of the width and height to remove the margins and padding.
To remove padding or margins from Google Charts and JavaScript, we can set the width and height options.
Sometimes, we want to modify a query string without reloading the page with JavaScript.
In this article, we’ll look at how to modify a query string without reloading the page with JavaScript.
To modify a query string without reloading the page with JavaScript, we can use the history.pushState method.
For instance, we write
const newUrl =
window.location.protocol +
"//" +
window.location.host +
window.location.pathname +
"?myNewUrlQuery=1";
window.history.pushState({ path: newUrl }, "", newUrl);
to create the newUrl URL string.
Then we call pushState with { path: newUrl } and newUrl to navigate to newUrl without reloading the page.
We get the current URL data from window.location.
We get the protocol with window.location.protocol.
host has the hostname.
pathname has the path before the query string.
To modify a query string without reloading the page with JavaScript, we can use the history.pushState method.
Sometimes, we want to add paste image from clipboard functionality with JavaScript.
In this article, we’ll look at how to add paste image from clipboard functionality with JavaScript.
To add paste image from clipboard functionality with JavaScript, we can listen to the document paste event and get the image from the paste event handler.
For instance, we write
document.onpaste = (event) => {
const items = (event.clipboardData || event.originalEvent.clipboardData)
.items;
console.log(JSON.stringify(items));
let blob = null;
for (let i = 0; i < items.length; i++) {
if (items[i].type.indexOf("image") === 0) {
blob = items[i].getAsFile();
}
}
if (blob !== null) {
const reader = new FileReader();
reader.onload = (event) =>{
console.log(event.target.result);
};
reader.readAsDataURL(blob);
}
};
to set document.onpaste function to a function that gets the image data.
In it, we get the clipboard data with
const items = (event.clipboardData || event.originalEvent.clipboardData)
.items;
Then we create the blob with a for loop that gets the item from the items array with type having the substring 'image' in it.
Then we use the FileReader object’s readAsDataURL to read the blob as a base64 image URL string.
And we get the image data with event.target.result in reader.onload.
To add paste image from clipboard functionality with JavaScript, we can listen to the document paste event and get the image from the paste event handler.
Sometimes, we want to reset Jest mock functions calls count before every test with JavaScript.
in this article, we’ll look at how to reset Jest mock functions calls count before every test with JavaScript.
To reset Jest mock functions calls count before every test with JavaScript, we can call mockClear on the mocked function or clearAllMocks to clear all mocks.
For instance, we write
afterEach(() => {
local.getData.mockClear();
});
to call local.getData.mockClear to clear the mocked local.getData method after each test by calling it in the afterEach callback.
We can use
afterEach(() => {
jest.clearAllMocks();
});
to call jest.clearAllMocks to clear all mocks after each test.
To reset Jest mock functions calls count before every test with JavaScript, we can call mockClear on the mocked function or clearAllMocks to clear all mocks.