Techformist

Comma operator in Javascript

📅 Dec 20, 2018 · 📝 Jun 9, 2020 · ☕ 2 min read

Did you know how to use comma operator in Javascript? A simple , can separate expressions in the same statement, evaluate left-to-right in the expression, pick the right most valid value as the result, and confuse other developers - all within the blink of an eye. We have discussed about operators when discussing operator precedence.

Javascript `typeof` issues and what to do about them

📅 Dec 19, 2018 · 📝 Jun 9, 2020 · ☕ 2 min read

typeof is useful but has inherent issues. There are gaps between what a developer expects in terms of consistency and what typeof delivers. Let us look at a few examples - 1 2 const i = 1; console.log(typeof i); // number typeof is a unary operator, and does not require brackets.

Array `copyWithin` - what's the point?

📅 Dec 18, 2018 · 📝 Jun 9, 2020 · ☕ 2 min read

You must have seen the copyWithin() method for an array, and surely wondered what it can do. copywithin copies elements from one position to another position in the same array. (Just kidding about the wondering thing - no one ‘wonders’ today, they just Google). 1 2 3 4 const fruits = ["apple", "orange", "grapes", "banana"]; fruits.

Find Difference Between Arrays in Javascript

📅 Dec 17, 2018 · 📝 Jun 9, 2020 · ☕ 1 min read

Use set and filter to find the difference between two arrays. 1 2 3 4 let fruits1 = ["apple", "orange", "grapes"]; let fruits2 = ["banana", "mango", "apple"]; let difFruits = [...new Set(fruits1)].filter((item) => !fruits2.includes(item)); console.log(difFruits); // [ 'orange', 'grapes' ] Similarly if you want to find the elements common in both arrays, you could employ a slightly different strategy.

Initiate Arrays with Data in Javascript

📅 Dec 16, 2018 · 📝 Apr 30, 2020 · ☕ 1 min read

Create arrays and initiate data in a single statement. Traditionally you would do the below to initiate the array and fill it with values - 1 let planets = ["mercury", "venus", "earth"]; This is a-ok if you know the values, but what if you want array to have fixed elements with pre-defaulted values?

Empty and reset objects in Javascript

📅 Dec 15, 2018 · 📝 Apr 30, 2020 · ☕ 2 min read

Is emptying objects akin to destroying them? Is destroying of objects easier than creating them? Let’s find out. Initiate an object. 1 2 let apple = { name: "apple", color: "red" }; console.log("apple: ", apple); // { name: 'apple', color: 'red' } Reset value 1 2 3 // the easy way to reset apple apple = {}; console.

Sleep Function in Javascript

📅 Dec 14, 2018 · 📝 Jun 9, 2020 · ☕ 1 min read

Sleep holds off your function execution for specified time. This is super useful whenever you want to hold off something for ‘x’ time. Here are two ways in which you can get your program to sleep for a while. setTimeOut 1 2 3 4 5 6 7 8 9 10 11 12 13 function sleep() { console.

Template Literals in Javascript

📅 Dec 13, 2018 · 📝 Jun 9, 2020 · ☕ 1 min read

Template literals provide an easily readable way to embed expressions within string literals. For example - 1 2 3 const thirdSmartPlanet = "earth"; const fact = `${thirdSmartPlanet}is flat`; console.log("fact: ", fact); // fact: earth is flat Earlier, you had to combine strings and variable like so -

Destructuring Variable Assignments in Javascript

📅 Dec 12, 2018 · 📝 Apr 30, 2020 · ☕ 3 min read

Destructuring assignment feature provides an easy, readable way to handle object and array assignments. ES6 introduced assignment destructuring, which provides a clean and more readable way to assign variables. The old way - 1 2 3 4 const fruits = { apple: { color: "red" }, orange: { color: "orange" } }; const appleTheFruit = fruits["apple"]; console.

Arrow Functions and `this` in Javascript

📅 Dec 11, 2018 · 📝 Jun 9, 2020 · ☕ 3 min read

Arrow functions have made our life much much easier. You can now refer to this without fearing the bogeyman. How did we write functions in the dark ages? Here’s a typical function. 1 2 3 4 5 6 function getSum(i, j) { // or const getSum = function(i,j) { return i + j; } console.

MeteorJS - Getting Started

📅 Dec 10, 2018 · 📝 Jun 9, 2020 · ☕ 3 min read

Meteor is quite an easy Javascript framework to pick up and I have been fascinated getting back to where I left off a couple of years ago. There are quite a few things that you could do in the first week itself, and could even target to complete real-world projects.

Generate Random Strings in Javascript

📅 Dec 9, 2018 · 📝 Jun 9, 2020 · ☕ 1 min read

Generate random strings in multiple ways in Javascript. Use crypto The quickest and easiest way to generate random strings. 1 2 3 const crypto = require("crypto"); var txt = crypto.randomBytes(10).toString("hex"); console.log("txt: ", txt); // a3f4ac84da8da6bf172b Crypto library is available in node. On the client side, use window.crypto.

Handle Exceptions in Javascript

📅 Dec 8, 2018 · 📝 Jun 9, 2020 · ☕ 3 min read

Get a quick-start on using try/catch to handle errors and exceptions. Consider the below example that expects name to be provided to the program. If name is provided you will go ahead and store record. 1 2 3 4 5 let name = ""; if (name) { // store record } The big problem with the above code is absence of any kind of feedback to the caller (or user).