Quickly check whether a property exists against an object. There is more than one way to check whether a given object has a prop - the choice if often convenience rather than performance of the said method. Let’s see the various methods by taking this example of a simple object.

Find and replace substring within a string using replace. If you know the exact substring use it directly in replace and be at peace. 1 2 3 let sample = "Lorem ipsum dolor sit amet ..."; sample = sample.replace("ipsum", "gypsum"); console.log("sample: ", sample); // Lorem gypsum dolor sit amet .

Here are some effective ways of inspecting variables used in your code using browser dev tools to your advantage. This is what we typically do in the code to know what exactly is happening with our variables. 1 2 var name = "Mr. Anderson"; console.log('before loop" + name); This will have the following beautiful output in browser console.

I am using Vue quite a bit and Vuelidate/ VeeValidate have spoilt me with options. The client-side validations are quite neat and easy to do. All you need is a couple of lines of code, some rules in the script section and you are good to go. However, you should not stop at this.

Catch duplicate attributes within an array of objects and retrieve unique elements. Array/object in question - 1 2 3 4 5 6 const students = [ { name: "Rama", grade: 10 }, { name: "Kris", grade: 5 }, { name: "Pete", grade: 7 }, { name: "Mo", grade: 5 } ]; We want to get unique grades from the array.

Set was introduced in ES6 and is a collection of values without keys. It has one killer feature that you want to use - filtering duplicates owing to its feature of allowing only unique values. So.. set? People from other languages may be familiar with sets, maps and arrays.. and the confusion that comes with them.

There are many great improvements provided by ES6 (introduced in Y2015), but I think a couple of them are really cool. String includes includes checks whether a certain (sub) string exists in the provided string. Note that this operation is case sensitive. 1 2 3 let str1 = "Neo rocks the world"; console.

We define a class and its variables like so - 1 2 3 4 5 6 7 8 9 10 11 12 class UserData { name = ""; type = ""; internalUserFlag = false; constructor({ name, type }) { this.name = name; this.type = type; } } const student1 = new UserData({ name: "Neo" }); console.

Extend a class and create a sub class for easier maintainability. Sub class can make use of special super functions to extend the functionality of a class. Using sub classes you can build out a complex logic in steps rather than as one messy module. See how to start with a Javascript class and class prototypes if you are new to Javascript classes.

Prototypes enable us to define attributes and functions of a class that can be shared across its object instances. Let us look at how we could start using prototypes in our Javascript classes. See how to start with a Javascript class if you are new to Javascript classes. Class in Javascript is built internally using prototypes - in fact that was the way some of us were reaching OOP nirvana in Javascript back in the day.

Class in Javascript is syntactic sugar on top of prototypes. Class makes it easier to structure our code, and to read and maintain it. Let’s see a simple class. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 class QuizTracker { constructor() { this.

Arrays in Javascript can be sorted using a simple .sort command. But, don’t let that simplicity deceive you - it goes far more than that. 1 2 let arr = [4, 2, 1, 7, 3]; console.log(arr.sort()); // [ 1, 2, 3, 4, 7 ] Sort can be used against full strings -

Array is a collection of elements or objects, and is quite easy to use in Javascript. Here’s an example of array: 1 const fruits = ["apple", "orange"]; You can print out the entire array.. 1 2 const fruits = ["apple", "orange"]; console.log("fruits: ", fruits); //fruits: [ 'apple', 'orange' ] .