Forem: Raj Maharjan

Delete merged branches using one command

Raj Maharjan — Fri, 30 Apr 2021 04:52:42 +0000

Here is a command that you can use to delete all the branches that have been merged to master branch from both local and remote using just one command. Instead of deleting branch one by one, I use below commands to delete all the branches that have been merged.

Delete local merged branches:

git branch --merged master | egrep -v "(^\*|master|dev)" | xargs -n 1 git branch -d

Delete remote merged branches:

git branch -r --merged master | egrep -v "(^\*|master|dev)" | cut -d/ -f2- | xargs -n 1 git push --delete origin

You can change branch name from master to any other branch name that you refer to as your main branch.

Also you can use it as alias by adding it in .bashrc file.

alias gclb='git branch --merged master | egrep -v "(^\*|master|dev)" | xargs -n 1 git branch -d'
alias gcrb='git branch -r --merged master | egrep -v "(^\*|master|dev)" | cut -d/ -f2- | xargs -n 1 git push --delete origin'

It has been a lot easier for me to use it this way. If you do it differently or have better way please comment below.

DOM Event delegation pattern

Raj Maharjan — Wed, 15 Jul 2020 12:40:13 +0000

If you have multiple button element with a similar callback function inside a div element, you can delegate event listeners to the parent div element instead of listening to each button.

// poor practice

<div>
  <button onclick="myFunction("red")">Red</button>
  <button onclick="myFunction("blue")">Blue</button>
  <button onclick="myFunction("black")">Black</button>
</div>

// good practice

<div onclick="myFunction(event)">
  <button id="red">Red</button>
  <button id="blue">Blue</button>
  <button id="black">Black</button>
</div>

// script

function myFunction(event) {
  let target = event.target;
  if (target.nodeName.toLowerCase() !== "button") {
    return;
  }

  // do something with id
  ...
}

The drawback is that you have to write a bit more code to filter out unnecessary events, but it will drastically increase the performance and provide cleaner code which outweighs the drawback significantly.

JavaScript Function declaration vs expression

Raj Maharjan — Sun, 05 Jul 2020 05:13:52 +0000

Function declaration:

appear in the global scope
appear inside a function

Features: Hoisting
Available: Anywhere inside scope (global and local)

Function expression:

can be assigned to a variable
can be assigned to a property
can appear in function invocations as parameters

Features: Closures, Callbacks, IIFE (Immediately Invoked Function Expressions)
Available: after the line it is declared

Convert string to number

Raj Maharjan — Wed, 24 Jun 2020 02:43:37 +0000

Because:

parseInt(n) as name suggests, parses and doesn't simply convert.

Caveats:

For later two, the string should only represent a number otherwise it will return NaN.
However, parseInt("10 apples") can still parse string that starts with a number.

Loop micro-optimization

Raj Maharjan — Thu, 18 Jun 2020 03:55:47 +0000

Because:

For loop uses one less variable
Count down to 0 is usually faster because it's more efficient to compare to 0 than others.

Difference between i++ and ++i

Raj Maharjan — Tue, 12 May 2020 01:42:02 +0000

Both prefix and postfix operators are used to mutate and update values. And both i++ and ++i alone does the same thing, increment the value of i by 1. This can sometimes be confusing for some beginners.

The difference can be found when assigned to other variables. For example:

let i = 0;
let j = i++; // first assigns to j then increments i by 1
console.log(j); // 0
let k = ++i; // first increments i by 1 then assigns to k
console.log(k); // 2