NoMethodError

NoMethodError is raised when a method is called on an object that doesn't define it. This commonly happens when calling a method on nil, or when there's a typo in the method name.

Common causes

• Calling a method on nil (e.g., user.name when user is nil)
• Typo in method name (e.g., user.nmae instead of user.name)
• Calling a private method from outside the class
• Missing require/include for a module
• Method defined in a different scope or class

How to fix it

• Use safe navigation operator (&.) to handle nil: user&.name
• Add nil checks before calling methods: user.name if user
• Use try() in Rails: user.try(:name)
• Check for typos in method names
• Ensure the correct module/gem is required

Example

# Error example
user = nil
user.name  # => NoMethodError: undefined method 'name' for nil:NilClass

# Fix with safe navigation
user&.name  # => nil (no error)

# Fix with conditional
user.name if user  # => nil (no error)

Related errors