What is your favourite function()?

curry function is probably my prefered one.
For those who don't know its utility, here's a basic example:

const divide = curry((a, b) => a / b)
const divide4By = divide(4)

console.log(divide4by(2))
// 2

I even made my own optimized version 😄
npmjs.com/package/super-curry.

I don't really have a favorite function, because it's all about using the right one to solve a problem. ut I like functions that make things simpler, so I think I'd pick fetch(). Because before, making HTTP requests from JavaScript looked like this

var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
     document.getElementById("demo").innerHTML = this.responseText;
    }
  };
  xhttp.open("GET", "ajax_info.txt", true);
  xhttp.send();

reduce is my favorite.

When something went unexpectedly wrong..

panic(error)

I don't know why but I just love sprintf() in php ... It's very useful and much more elegant than just endlessly concatenate strings !

And less elegant but really useful once again, die(var_dump()) has a special place in my heart ...

list.zip (other).map ((a,b) =>...)

In Ruby, backticks are a function call. And what's especially cool is that heredocuments with backticks call the same function, but with multi line arguments. So you can define them to do other, more interesting things, like call out to other languages! In practice, I mostly use it when experimenting with some slightly tedious external resource, I basically learned PostgreSQL by running them through these kinds of functions.

require 'open3'

def `(str)
  Open3.capture3('php', stdin_data: str).first
end

<<~`PHP` # => "hello cruel world\n"
hello \
<?php echo "cruel" ?> \
world
PHP

In PHP I always include file with my custom helper functions. These two wrap output with <pre/> tags, which allows nice&quick debugging via browser from any class or template code.

function pre($obj = null, $escape = false){
    echo "<pre>";
    if($escape){
        $obj = htmlspecialchars ( print_r($obj, true) );
    }
    print_r($obj);
    echo "</pre>";
}

function dump($obj = null){
    echo "<pre>";
    var_dump($obj);
    echo "</pre>";
}

Love throwing exceptions around ;)

throw new Exception("...");
throw Error("...");
raise Exception.Create('...');

map, filter, reduce, forEach, Array.prototype.some, Array.prototype.every

Working with array in Javascript never been easier.
Love it all!