Random stuff that is valid JS

random.js

var a = null;

function b(c) { var d = ['abc']; return d.find(e => e === c)}

if (Boolean(a)) console.log('True'); // True

if (!Boolean(a)) console.log('True'); // nothing

b('h') // undefined

b('abc') // abc

if (Boolean((a = b('abc')))) console.log('True', a); // True abc


if (Boolean((a = b('abcd')))) console.log('True', a); // nothing

I think the goal here was to demonstrate variable reassignment within the evaluation of an if statement. The use case was that function b was an expensive function that I only wanted to run once but I needed to assign the result to variable a only if the function returned a valid result.