Using throw in a Javascript expression

You can make use of the functional nature of javascript:

var setting = process.env.SETTING ||                function(){                  throw "please set the SETTING environmental variable";               }();// es201xvar setting = process.env.SETTING ||               (() => {throw `SETTING environmental variable not set`})();

or more generic create a function to throw errors and use that:

function throwErr(mssg){    throw new Error(mssg);}var setting = process.env.SETTING ||                throwErr("please set the SETTING environmental variable");

A snippet I use:

const throwIf = (  assertion = false,   message = `An error occurred`,   ErrorType = Error) =>       assertion && (() => { throw new ErrorType(message); })();throwIf(!window.SOMESETTING, `window.SOMESETTING not defined`, TypeError);