Side Effects

For handling side effects there are a couple of functions, the underlying concept of which is to not interfere with the main execution flow:

import inject from 'fnts/inject';

const computeAndLog = inject(
  compute,
  (...args) => console.log('Computing with args: ', args)
);

computeAndLog(1, 2, 3);

The above one, inject, makes sure to leave the original function as is, giving us the ability to perform a side effect on its every call.

A couple more, tap and rethrow, perform exactly that, only tap returns (passes through) the received argument, and rethrow, you've guessed it, rethrows an error.

Both use inject under the hood, which means it can be used to create more side effect "creators", e.g. a simple logger, like in the example above:

import inject from 'fnts/inject';

const logFn = inject(console.log);