Ruby on Rails latest stable (v5.2.3) - 2 notes - Class: Module

Method deprecated or moved

This method is deprecated or moved on the latest stable version. The last existing version (v5.0.0.1) is shown here.

alias_method_chain(target, feature) public

NOTE: This method is deprecated. Please use Module#prepend that comes with Ruby 2.0 or newer instead.

Encapsulates the common pattern of:

alias_method :foo_without_feature, :foo
alias_method :foo, :foo_with_feature

With this, you simply do:

alias_method_chain :foo, :feature

And both aliases are set up for you.

Query and bang methods (foo?, foo!) keep the same punctuation:

alias_method_chain :foo?, :feature

is equivalent to

alias_method :foo_without_feature?, :foo?
alias_method :foo?, :foo_with_feature?

so you can safely chain foo, foo?, foo! and/or foo= with the same feature.

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August 29, 2008
10 thanks

Always pass a block

I highly recommend always taking a block and passing it back up the chain if you use alias_method_chain, even if the original method does not. Otherwise you’re keeping anyone later in the chain from adding support for blocks.


April 1, 2009 - (>= v2.1.0)
2 thanks