Category: JavaScript Answers

Sometimes, we want to detect the onload event of a window opened with window.open with JavaScript.

In this article, we’ll look at how to detect the onload event of a window opened with window.open with JavaScript.

How to detect the onload event of a window opened with window.open with JavaScript?

To detect the onload event of a window opened with window.open with JavaScript, we set the popup’s onload method.

For instance, we write

const popup = window.open(location.href, "snapDown");
popup.onload = () => {
  alert("message one");
};

to call window.open to open a popup window that opens the location.href URL.

Then we set its onload property to a function that’s run when the popup window finishes loading.

Conclusion

To detect the onload event of a window opened with window.open with JavaScript, we set the popup’s onload method.

Sometimes, we want to search for a string inside an array of strings with JavaScript.

In this article, we’ll look at how to search for a string inside an array of strings with JavaScript.

How to search for a string inside an array of strings with JavaScript?

To search for a string inside an array of strings with JavaScript, we use the array find method.

For instance, we write

const strs = ["abc", "def", "ghi", "jkl", "mno"];
const value = "abc";
const result = strs.find((str) => str === value);

to call the strs.find method with a callback that checks is str in strs equals value.

If it’s true, the value is returned.

Conclusion

To search for a string inside an array of strings with JavaScript, we use the array find method.

To update a JSON object using JavaScript, we can use a loop.

For instance, we write

for (const o of jsonObj) {
  if (o.id === 3) {
    o.username = "Thomas";
    break;
  }
}

to loop through the objects in the jsonObj array.

In the loop, we find the item with id 3.

If it’s true, then we set its username property value to 'Thomas'.

Conclusion

To update a JSON object using JavaScript, we can use a loop.

Sometimes, we want to reliably hash JavaScript objects.

In this article, we’ll look at how to reliably hash JavaScript objects.

How to reliably hash JavaScript objects?

To reliably hash JavaScript objects, we can use the object-hash package.

We install the package by running

npm i object-hash

Then we write

const hash = require("object-hash");
const testObj = { a: 1, b: 2 };

console.log(hash(testObj));

to call hash with testObj to return a hash string created from the testObj object.

Conclusion

To reliably hash JavaScript objects, we can use the object-hash package.

Sometimes, we want to get the size of an array in an object with JavaScript.

In this article, we’ll look at how to get the size of an array in an object with JavaScript.

How to get the size of an array in an object with JavaScript?

To get the size of an array in an object with JavaScript, we use the length property.

For instance, we write

const st = {
  itema: {},
  itemb: [{ id: "s01" }, { id: "s02" }],
};

console.log(st.itemb.length);

to get the st.itemb array.

And then we use its length property to get the size of the array.

Conclusion

To get the size of an array in an object with JavaScript, we use the length property.