Category: JavaScript Answers

Sometimes, we want to set request timeout with Fetch API.

In this article, we’ll look at how to set request timeout with Fetch API.

How to set request timeout with Fetch API?

To set request timeout with Fetch API, we can use the AbortController constructor.

For instance, we write

const controller = new AbortController();

const timeoutId = setTimeout(() => controller.abort(), 5000);

const req = async () => {
  const response = await fetch(url, { signal: controller.signal });
  //...
  clearTimeout(timeoutId);
};
req();

to create an AbortController object.

Then we call abort in the setTimeout function to cancel the request that’s been assigned the abort controller signal object after 5 seconds.

Then we call fetch with the url to make the request to and the signal property of the object in the 2nd argument is set to controller.signal.

Assigning signal to controller.signal lets us abort the request with controller.abort.

After the request is done, we call clearTimeout with the timeoutId to cancel the setTimeout timer.

If the timer is cancelled after 5 seconds, then abort runs and the request will be cancelled.

Conclusion

To set request timeout with Fetch API, we can use the AbortController constructor.

Sometimes, we want to get element by class name with JavaScript.

In this article, we’ll look at how to get element by class name with JavaScript.

How to get element by class name with JavaScript?

To get element by class name with JavaScript, we can use the getElementsByClassName method.

For instance, we write

const els = [...document.getElementsByClassName("foo")];

to call getElementsByClassName with 'foo' to return all the elements with class foo in a node list.

Then we spread the node list entries into an array with ...

Conclusion

To get element by class name with JavaScript, we can use the getElementsByClassName method.

Sometimes, we want to get all attributes from a HTML element with JavaScript.

In this article, we’ll look at how to get all attributes from a HTML element with JavaScript.

How to get all attributes from a HTML element with JavaScript?

To get all attributes from a HTML element with JavaScript, we can use the attributes property of the element.

For instance, we write

const elem = document.querySelector("[name=test]");
const attrs = [...elem.attributes].map(
  (attr) => attr.nodeName
);

console.log(attrs);

to select the element with querySelector.

And then we get the attributes with elem.attributes.

Next, we spread the entries of attributes NodeMap into an array.

And we get the name of each attribute with nodeName.

Conclusion

To get all attributes from a HTML element with JavaScript, we can use the attributes property of the element.

Sometimes, we want to fix var.replace is not a function with JavaScript.

In this article, we’ll look at how to fix var.replace is not a function with JavaScript.

How to fix var.replace is not a function with JavaScript?

To fix var.replace is not a function with JavaScript, we should make the variable we’re calling replace on is a string.

For instance, we write

const trim = (str) => {
  return str.toString().replace(/^\s+|\s+$/g, "");
};

to define the trim function that takes the str parameter.

To make sure that str is a string, we call toString to convert it to a string before we call replace on it.

Conclusion

To fix var.replace is not a function with JavaScript, we should make the variable we’re calling replace on is a string.

Sometimes, we want to convert Blob to File in JavaScript.

In this article, we’ll look at how to convert Blob to File in JavaScript.

How to convert Blob to File in JavaScript?

To convert Blob to File in JavaScript, we can use the File constructor.

For instance, we write

const file = new File([myBlob], "name");

to create a File object with the myBlob blob object in the array.

The 2nd argument is the file name string.

Conclusion

To convert Blob to File in JavaScript, we can use the File constructor.