Techformist

Class Methods and Comma in Javascript

📅 Apr 26, 2019 · 📝 Apr 30, 2020 · ☕ 2 min read

Where does a comma fit in the class methods? No where. Where do I remember it from, then - Vue objects. When I started using Vue full time some time in 2017, I had this problem with putting commas everywhere. These were becoming like issues with semicolons - except that VS Code Prettier takes care of my semi-colons.

Newbie Mistakes in Creating Promises in Javascript

📅 Apr 25, 2019 · 📝 Apr 30, 2020 · ☕ 5 min read

Promises and promise chaining - really powerful tools to use and make your life as easy as it can be. Until you are stuck in an error that no one seems to have a clue about. Let us see some common errors and how to fix them. 1. Not use error handling in promises It does not demand a lot, people.

Chain Promises in Javascript

📅 Apr 24, 2019 · 📝 Apr 30, 2020 · ☕ 3 min read

A chain promises to process data through a promise-laden gold field. A simple promise - 1 2 3 4 5 6 7 8 9 10 11 let promiseToLog = new Promise(function(resolve, reject) { console.log("started"); setTimeout(function() { resolve("promise fulfilled.. after timeout"); }, 300); }); console.log("promise initialized"); promiseToLog.then(function(val) { console.log("resolver", val); }); As you have seen earlier the promise gets initialized and next statement (‘promise initialized’) gets executed without waiting to resolve promise.

Ways to a Promise in Javascript

📅 Apr 23, 2019 · 📝 Apr 30, 2020 · ☕ 3 min read

You already know that promises enable us to carry out asynchronous transactions. How do you implement in your own programs? I assume you already know what promises do in Javascript](/promises-javascript) and how event driven programming works :) Javascript promise is an object. So, Promise should be as easy as using an object.

Promises in Javascript

📅 Apr 22, 2019 · 📝 Apr 30, 2020 · ☕ 3 min read

Promises enable us to carry out asynchronous transactions. Javascript promise is an object, as we all are. It is a way for the program to initiate “something”, and not wait for the process to complete (='async operations’). Runtime engine calls the call back function once the process completes - thereby completing the loop.

Event Driven Programming

📅 Apr 21, 2019 · 📝 Apr 30, 2020 · ☕ 3 min read

Javascript is an event-driven programming language. Logic is triggered by a user or system action, and the flow of action continues to be determined by events along the way. These events can be user-input like clicks, system operations like completion of DB read, completion of file load, etc. Events are handed by the event handlers that are defined by you or the underlying ecosystem.

Delete Array Elements while Iterating Array in Javascript

📅 Apr 20, 2019 · 📝 Oct 13, 2020 · ☕ 2 min read

Removing array elements while iterating through the elements in a loop can be tricky for a beginner. Consider this - 1 2 3 4 5 6 const nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; for (let i = 0; i < nums.length; i++) { console.

Typeof Cheatsheet in Javascript

📅 Apr 19, 2019 · 📝 Apr 30, 2020 · ☕ 1 min read

Here’s a quick reference of various values and their types. For further reference: see what types mean in Javascript and type casting in Javascript. Value Type Description true boolean Boolean 1 number Number “1” string String “abcd” string String Boolean(false) object Boolean object Number(0) object Number object String(“abcd”) object String object [1, 2, 3] object Array object Object() object Plain object {} object Plain object function() {} function Function object Code to cross-check -

Avoid Array Constructors in Javascript

📅 Apr 18, 2019 · 📝 Apr 30, 2020 · ☕ 1 min read

Array constructor syntax is confusing to both the system and humans. Avoid it when possible. Consider this.. 1 2 3 const planets = ["mercury", "venus", "earth"]; console.log(planets[0]); // mercury Now, let’s say we do the same using a constructor. 1 2 3 4 const num = new Array(3, 1, 4, 5); console.

Faster Loops in Javascript

📅 Apr 17, 2019 · 📝 Apr 30, 2020 · ☕ 2 min read

We have come to appreciate the performance and readability of the ol’ for loop. But, just how much should we be appreciating the performance? We already did a huge scientific study on different avatars of for. This is the time that we do another highly ineffective test for different types of loops so that we can prove nothing to no one.

Don't Update Function Argument Values

📅 Apr 16, 2019 · 📝 Apr 30, 2020 · ☕ 2 min read

Do not change those non-primitive function arguments without understanding the significant implications of your action. Programming languages have pass by reference and pass by value to pass arguments to a function. Javascript passes values for primitives, but references when you are trying to pass objects. Changing arguments within a function will change the arguments for ever.

Problem with Multiplication of Decimal Numbers in Javascript

📅 Apr 15, 2019 · 📝 Apr 30, 2020 · ☕ 2 min read

Things are always not how they appear. Especially when it comes to multiplication of decimal numbers in Javascript. Consider - 1 const a = 1.1; Multiply the above number by 3. Compare with expected answer just to make sure you are not seeing a wrong answer. 1 2 3 4 5 6 const a = 1.

Immutability Using Object Seal in Javascript

📅 Apr 14, 2019 · 📝 Apr 30, 2020 · ☕ 2 min read

What if you want to allow changing props of an object, but do not want anyone to add new props? Well, that is what Object.seal is for. Objects in Javascript cannot be made immutable by using a const keyword. const works on primitives. It can also make sure you don’t reassign value to an object.