JavaScript

Free static function

A free static function is one that can be provided as a call back and it will be run fine:

Firefox v122 console session
function run(cb) {
  return cb();
}

run(Math.random);
//=> 0.20621770135266349

run(crypto.randomUUID);
// ~ Uncaught TypeError: 'randomUUID' called on an object that
// ~ does not implement interface Crypto.

Once, log was not a free static method of console, which meant this didn’t work:

A long time ago…​
var log = console.log;

log('hello');
// ~ Illegal invocation (back in the day)

But we could use something like Function.prototype.bind:

var log = console.log.bind(console);

log('hello');
//=> hello

Nowadays we can simply do const log = console.log and it works on most, if not all JavaScript engines. It works with console.info/error/table/etc. as well.