Understanding Ruby’s `tap` — A Powerful Debugging and Configuration Tool

Ruby’s Object#tap is a small but powerful method that often goes unnoticed. It allows you to “tap into” a method chain, perform some operation, and return the original object—regardless of what the block inside returns. This makes it particularly useful for debugging, configuration, or inserting side effects without breaking the flow of your code. A Simple Use Case: Debugging Take the following example: 1 n = [1,2,3].map { _1 % 2 }.map { _1 * 10 } This returns [10, 0, 10]. But what if that’s not what you expected? You might want to inspect the result of the first map: 1 2 3 4 n = [1,2,3].map { _1 % 2 } puts n.inspect n = n.map { _1 * 10 } puts n.inspect Using tap, we can make this more elegant: 1 2 3 4 n = [1, 2, 3].map { _1 % 2 } .tap { puts _1.inspect } .map { _1 * 10 } .tap { puts _1.inspect }