Category: JavaScript Answers

Sometimes, we want to load an image from URL into buffer in Node.js and JavaScript.

In this article, we’ll look at how to load an image from URL into buffer in Node.js and JavaScript.

How to load an image from URL into buffer in Node.js and JavaScript?

To load an image from URL into buffer in Node.js and JavaScript, we use Axios.

For instance, we write

const response = await axios.get(url, { responseType: "arraybuffer" });
const buffer = Buffer.from(response.data, "utf-8");

to make a get request to the image url with axios.get.

We get the response as an array buffer by setting the responseType to 'arraybuffer'.

And then we call Buffer.from to convert the response.data response we get from the promise returned by get body to a buffer.

Conclusion

To load an image from URL into buffer in Node.js and JavaScript, we use Axios.

Sometimes, we want to set a JavaScript onclick event to a class with CSS.

In this article, we’ll look at how to set a JavaScript onclick event to a class with CSS.

How to set a JavaScript onclick event to a class with CSS?

To set a JavaScript onclick event to a class with CSS, we loop through each element and set its onclick property to the click handler.

For instance, we write

const elements = document.getElementsByClassName("someClassName");

for (const element of elements) {
  element.onclick = () => {
    console.log("Clicked in an element of the class.");
  };
}

to select all elements with class someClassName with getElementsByClassName.

Then we loop through each element with a for-of loop and set their onclick property to their click handler functions.

Conclusion

To set a JavaScript onclick event to a class with CSS, we loop through each element and set its onclick property to the click handler.

Sometimes, we want to add another class to a div with JavaScript.

In this article, we’ll look at how to add another class to a div with JavaScript.

How to add another class to a div with JavaScript?

To add another class to a div with JavaScript, we call classList.add.

For instance, we write

document.getElementById("hello").classList.add("someClass");

to select the element with getElementById.

Then we call its classList.add method to add the someClass class to it.

Conclusion

To add another class to a div with JavaScript, we call classList.add.

Sometimes, we want to convert seconds to a date object with JavaScript.

In this article, we’ll look at how to convert seconds to a date object with JavaScript.

How to convert seconds to a date object with JavaScript?

To convert seconds to a date object with JavaScript, we create a date with timestamp 0 and add the seconds we want to it.

For instance, we write

const toDateTime = (secs) => {
  const t = new Date(1970, 0, 1);
  t.setSeconds(secs);
  return t;
};

to define the toDateTime function.

In it, we create a date with timestamp 0.

Then we call setSeconds to add secs` seconds to it.

Finally we return the t date.

Conclusion

To convert seconds to a date object with JavaScript, we create a date with timestamp 0 and add the seconds we want to it.

Sometimes, we want to make a time delayed redirect with JavaScript.

In this article, we’ll look at how to make a time delayed redirect with JavaScript.

How to make a time delayed redirect with JavaScript?

To make a time delayed redirect with JavaScript, we call setTimeout.

For instance, we write

setTimeout(() => {
  location.href = "http://www.example.com";
}, 1500);

to call setTimeout with a callback that sets location.href to "http://www.example.com" to redirect to http://www.example.com after 1500ms.

Conclusion

To make a time delayed redirect with JavaScript, we call setTimeout.