How do JavaScript closures work?

A closure is a function plus the scope it was created in. That sentence is correct and explains nothing until you watch two of them refuse to share a variable.

How to change a Git commit message

Fixing the last commit message is one command. Fixing an older one rewrites every commit after it, which is fine while nothing has been pushed and a problem the moment it has.

How to check out a remote Git branch

A colleague pushed a branch and you want to work on it. In current git that is one command — but only after a fetch, and only if you avoid the one form that leaves you on no branch at all.

How to concatenate two lists in Python

There are five reasonable ways to join two lists. They differ in whether you get a new list or modify an existing one, and that difference is visible to other code holding the same list.

How to convert a string to a boolean in JavaScript

The reason this question has 111 answers is one line:

Boolean("false") = true

How to copy a file in Python

shutil offers four functions for this and they differ in what they carry across. As of Python 3.14 there is also a pathlib method, which every answer written before then predates.

How to create a UUID in JavaScript

There is a built-in for this now, so the answer is one line. The part worth reading is why the Math.random() one-liner that still circulates produces something that looks identical and is not.

How to deep clone an object in JavaScript

There is a built-in for this now — structuredClone. The question was asked in 2008 and got the answer it deserved at the time; the interesting part today is what each option quietly does to your data.

How to delete a Git branch locally and remotely

A branch exists in up to three places: on your machine, on the remote, and as a remote-tracking ref that remembers what the remote looked like last time you asked. Deleting it properly means dealing with all three.

How to force git pull to overwrite local files

You have local edits, the remote has moved on, and you want the remote’s version — all of it, yours discarded. git pull refuses, so the obvious next move is to add --force. That does not work, and it is worth seeing why.