Category: JavaScript

Sometimes, we want to sort an object by value in JavaScript.

In this article, we’ll look at how to sort an object by value in JavaScript.

Sort an Object by Value in JavaScript

To sort an object by value in JavaScript, we can use the Object.values method to get the property values from the object in an array.

Then we can use the JavaScript sort method to sort the array values.

For instance, we can write:

const dict = {
  "x": 1,
  "y": 6,
  "z": 9,
  "a": 5,
  "b": 7,
  "c": 11,
  "d": 17,
  "t": 3
};

const items = Object.values(dict).sort((first, second) => {
  return second - first;
});

console.log(items)

We create the dict object with values we want to sort.

Then we call Object.values with dict to return an array of dict property values.

Next, we call sort with a callback that returns how we want to sort the items.

We subtract second by first to sort the property values in descending order.

Therefore, the console log logs:

[17, 11, 9, 7, 6, 5, 3, 1]

Conclusion

To sort an object by value in JavaScript, we can use the Object.values method to get the property values from the object in an array.

Then we can use the JavaScript sort method to sort the array values.

Sometimes, we may want to run code when the DOM is loaded without using jQuery.

Therefore, we need to find an equivalent of jQuery’s $(document).ready in plain JavaScript.

In this article, we’ll look at how to find the equivalent of jQuery’s $(document).ready in plain JavaScript.

Equivalent of jQuery’s $(document).ready in Plain JavaScript

To find the equivalent of jQuery’s $(document).ready in plain JavaScript, we can listen to the DOMContentLoaded event on the document object with the addEventListener method.

To do this, we write:

document.addEventListener("DOMContentLoaded", (event) => {  
  console.log('document ready')  
});

to listen to the DOMContentLoaded event on document .

We call document.addEventListener with an event handler callback as the 2nd argument that runs when the DOM is successfully loaded.

Therefore, when the page is loaded, we should see 'document ready' logged.

Conclusion

To find the equivalent of jQuery’s $(document).ready in plain JavaScript, we can listen to the DOMContentLoaded event on the document object with the addEventListener method.

Sometimes, we may run into the “unexpected token o” error when parsing JSON in our JavaScript app.

In this article, we’ll look at how to fix the “unexpected token o” error when trying to parse JSON in Our JavaScript app.

Fix the “unexpected token o” Error When Trying to Parse JSON in Our JavaScript App

To fix the “unexpected token o” error when trying to parse JSON in Our JavaScript app, we should make sure that we’re running JSON.parse on a valid JSON string.

For instance, instead of writing something like:

const obj = {  
  foo: 'bar'  
}  
console.log(JSON.parse(obj))

where we’re trying to call JSON.parse on the obj object, we should make sure that we’re calling JSON.parse on a valid JSON string.

For example, we write:

const obj = JSON.stringify({  
  foo: 'bar'  
})  
console.log(JSON.parse(obj))

to convert the object into a JSON string with JSON.stringify .

Then we can call JSON.parse successfully to parse the JSON string back into an object.

The console log should log:

{foo: "bar"}

Conclusion

To fix the “unexpected token o” error when trying to parse JSON in Our JavaScript app, we should make sure that we’re running JSON.parse on a valid JSON string.

Sometimes, we may run into the ‘Error: listen EADDRINUSE’ error when running a Node.js app.

In this article, we’ll look at how to fix the ‘Error: listen EADDRINUSE’ error when running a Node.js app.

Fix the ‘Error: listen EADDRINUSE’ Error When Running a Node.js App

To fix the ‘Error: listen EADDRINUSE’ error when running a Node.js app, we should make sure that no process is running on the same port that the Node.js app is running on.

For instance, if we have the following Express app code:

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('hello world')
});

app.listen(port, () => {
  console.log(`Example app listening at http://localhost:${port}`)
})

Then we should make sure that no process is running on port 3000 before we run our Express app.

Conclusion

To fix the ‘Error: listen EADDRINUSE’ error when running a Node.js app, we should make sure that no process is running on the same port that the Node.js app is running on.