Ruby 2.5 adds yield_self and other new core methods

Ruby 2.5 introduced some elegant features that make writing expressive and clean code easier. One such feature is yield_self, a method that brings in a functional programming flavor to Ruby’s already flexible syntax.

What is yield_self?

yield_self is a method that passes the receiver to a block and returns the block’s result. It’s particularly useful when you want to start a chain with an object, pass it through a transformation, and continue chaining.

How is it different from tap?

You might be familiar with tap, which also yields the receiver to a block. However, there is a key difference:

• tap returns the original object after yielding it.
• yield_self returns the result of the block.

Example: tap vs yield_self

1# Using tap
210.tap { |n| puts n + 1 } # prints 11
3# => 10 (returns the original object)
4
5# Using yield_self
610.yield_self { |n| n + 1 }
7# => 11 (returns the result of the block)

When to use yield_self

Use yield_self when you want to apply a transformation to an object mid-chain or when you want to perform operations where each step returns a different object.

1"5".yield_self { |s| Integer(s) }.yield_self { |i| i * 2 }
2# => 10

It’s especially useful in functional-style pipelines:

1result = user_input
2  .yield_self { |s| s.strip }
3  .yield_self { |s| s.downcase }
4  .yield_self { |s| s.gsub(/[^a-z]/, '') }

Other notable Ruby 2.5 features

• Top-level rescue inside do/end blocks — now you can write begin ... rescue ... end inline more concisely.
• do/end blocks now return — making multi-line lambdas easier to use.
• Improved error backtraces — cleaner and easier to navigate.

Summary

yield_self gives Ruby developers a powerful and elegant way to chain transformations, especially in contexts where intermediate values need to be passed along in a clean and readable manner. It's a small but impactful addition to the Ruby toolbox that promotes a more functional programming style without sacrificing clarity.

For full details on Ruby 2.5, check out the official release notes.