Let’s be honest, how many times you found yourself in situations like this:

void someMethod() {
	if (condition1) {
		if (condition2) {
			if (condition3) {
				doSomething();
			} else {
				debugPrint('Problem 3');
			}
		} else {
			debugPrint('Problem 2');
		}
	} else {
		debugPrint('Problem 1');
	}
}

Countless times, perhaps even worse than that, especially at the beginning of our developer careers. The more conditions you nest, the more your code will get like this:

void someMethod() {
	if (condition1) {
		if (condition2) {
			if (condition3) {
				if (condition4) {
					if (condition5) {
						if (condition6) {
							if (condition7) {
								if (condition8) {
									doSomething();

It can get pretty ugly and make the code reading process very frustrating. There is a better, more intuitive and read-friendly way to do it.

Guard Clauses

A guard clause consists of an expression that must evaluate whether code execution should continue. In a nutshell, instead of nesting multiple if conditions one inside another, we create guard clauses that individually checks if there is a problem before executing the main code. Let’s have a look at the transformation from the example above to the guard clauses technique:

void someMethod() {
	if (!condition1) {
		debugPrint('Problem 1');
		return;
	}
	if (!condition2) {
		debugPrint('Problem 2');
		return;
	}
	if (!condition3) {
		debugPrint('Problem 3');
		return;
	}
	
	doSomething();
	return;
}

Much more readable right?

Now is much simpler to add new conditions without messing up the code.