This content originally appeared on DEV Community and was authored by simc dev
JavaScript is the most popular language and this language that you can learn easily by yourself. it's front-hand language. And it's one of the languages used by coders, developers, and programmers. Not to be confused with JScript, Java, or Javanese script that all are similar languages.
1. A quick way to using slice and ES8 PadStart method
const accountnum = "204910110001957";
const lastFourDigits = accountnum.slice(-4);
// print last four digit of account number
const maskedNumber = lastFourDigits.padStart(accountnum.length, '*');
console.log(lastFourDigits); // output will be 1957
console.log(maskedNumber); // ***********1957
2. Run an event handler only one time
If you want to run the addEventListener method you have to pass {once: true} as the third argument then the event handler method will run only one time.
document.getElementById("btn").addEventListener("click",
function () {
console.log("Button is Clicked..");
},
{ once: true }
);
3. Update an object's properties by spread operator
const object = {
name: "Rahil",
age: 29,
city: "Surat",
};
const newAge = 49;
const updatedObject = {
...object,
age: newAge
};
console.log(object); // { name:"Rahul", age:29, city:"Surat"}
console.log(updatedObject); // { name:"Rahul", age:49, city:"Surat"}
4. Find the length of properties in an object
Const Object = {
id: 1,
name: 'Arun',
age: 30
}
console.log(Object.keys(object).length);
5. Print the last elements of an array
const elements = [5,6,7,8,9,10];
const last = elements.slice(-1);
console.log(last); // Output will be 10
const secondLast = elements.slice(-2);
console.log(secondLast); // Output will be 9,10
Provide a dynamic key for an object
function obj(key, value) {
const dyn = {
[key]: value
};
return dyn;
}
console.log(obj('name', 'Rahul')); // Output will be name: Rahul
console.log(obj('age', '29')); // Output will be age: 29
6. Convert any type of value to boolean
In JavaScript, there are two types of boolean values true and false. You can use the Boolean() function to find out if a variable is true or not.
let num1;
console.log(!!num1); // false
const num2 = 10;
console.log(!!num2); // true
const n1 = 'Tim';
console.log(!!n1); // true
const n2 = '';
console.log(!!n2); // false
This content originally appeared on DEV Community and was authored by simc dev
simc dev | Sciencx (2022-07-18T04:30:50+00:00) Useful Tips & Tricks In JavaScript. Retrieved from https://www.scien.cx/2022/07/18/useful-tips-tricks-in-javascript-3/
Please log in to upload a file.
There are no updates yet.
Click the Upload button above to add an update.