Performance and good error handling play a significant role in development.

Smart use of short-circuit evaluation can help immensely in these cases.

It is a core concept in many programming languages, but this article will focus on JavaScript to showcase examples and use cases.

What is a Short-Circuit Evaluation?

Short-circuit evaluation is a programming concept used with logical operands AND (&&) and OR (||).

It lets the compiler skip the execution of part of an expression if the outcome was already determined by the first operand.

The logic goes like this:

• Using &&, if the first operand is false, the second operand will not be evaluated.

• Using ||, if the first operand is true, the second operand will not be evaluated.

Performance Benefits of Short-Circuit Evaluation

If you have a resource-intensive function as a second operand, you might want to avoid calling it if it’s unnecessary.

See the example below:

fetchDataFromDatabase() is only called when loadData is true.

This helps to avoid costly database operations when not needed.

Aid for Better Error Handling

With Short-Circuit Evaluation you might as well prevent runtime errors by checking for undefined and null values:

In this example userProfile is null if user is null, this logic helps to prevent TypeErrors and ensures safe property access.

Short-Circuit Evaluation in React

In React there is a concept called Conditional Rendering.

It can use the same Short-Circuit Evaluation logic to evaluate if a UI element needs to be rendered based on a given condition:

The span element is only rendered if a user is not null.

In cases where resource-intensive UI elements have to be rendered, conditional rendering can improve performance.

Conclusion

Short-circuit evaluation is a great way to enhance performance and error handling.

By correctly implementing this concept, you can write more efficient and safer code.