Use instance_of? for class comparison

Cette page n'est pas encore disponible en français, sa traduction est en cours.
Si vous avez des questions ou des retours sur notre projet de traduction actuel, n'hésitez pas à nous contacter.

Metadata

ID: ruby-best-practices/class-comparison

Language: Ruby

Severity: Notice

Category: Best Practices

Description

In Ruby, it is recommended to use the instance_of? method for class comparison. This is because instance_of? only returns true if the object is an instance of that exact class, not a subclass. The method provides a strict way of checking an object’s class, which helps in maintaining the integrity of the code.

Using other methods such as something.class == Date or something.class.equal?(Date) are not considered good coding practice. These methods could lead to unwanted behavior, particularly if the object’s class is a subclass of the specified class.

To adhere to this rule, always use something.instance_of?(Date) when you need to check if an object is an instance of a specific class. This ensures the object is exactly an instance of the class, not a subclass, providing more accurate and reliable results. This practice can help avoid potential bugs and make your code more robust and easier to understand.

Non-Compliant Code Examples

something.class == Date
something.class.equal?(Date)
something.class.eql?(Date)
something.class.name == 'Date'
something.class.name == "Date"

Compliant Code Examples

something.instance_of?(Date)
https://static.datadoghq.com/static/images/logos/github_avatar.svg https://static.datadoghq.com/static/images/logos/vscode_avatar.svg jetbrains

Seamless integrations. Try Datadog Code Analysis

PREVIEWING: may/unit-testing