go-defer-in.js

// emulation of Go's defer in JS

// helper function 
const makeDefer = () => {
	const deferred = [];
	return {
		defer(f) {
			deferred.unshift(f);
		},
		done(result) {
			deferred.forEach(f => f());
			return result;
		}
	}
}
//---- usage---------------
function compute(x) {
	const { defer, done } = makeDefer();
	const result = {doubled: 0, incremented: 0};
	defer(() => {
		console.log("incremented");
		result.incremented = x + 1;
	});

	defer(() => {
		console.log("doubled");
		result.doubled = x * 2;
	});
	console.log("compute");

	return done(result);
}

console.log(compute(123));

/*
console output:

compute
doubled
incremented
{ doubled: 246, incremented: 124 }*/