Tap combinator
A tap combinator applies an operation to a value for its side effects and returns the original value unchanged.
The Well-Grounded Rubyist, Fourth Edition
tap yields its receiver to a supplied block and then returns that receiver unchanged as the method result.
- How it is used
- Uses tap to execute side-effecting or observational block code while preserving the receiver for subsequent operations.
- How deep it goes
- Explains yielding, unchanged return, chaining, and bang-method edge cases, but stops short of implementation internals.
- Examples
- Demonstrates printing an uppercased string, reversing after tap, and applying gsub! inside the block.
- What you can do after
- Apply it via Ruby method chains to inspect or modify receivers without replacing the chain's value.
Read how The Well-Grounded Rubyist, Fourth Edition explains tap combinator →
Functional Programming in JavaScript
A combinator that applies a function to a value for its side effects and then returns the original value unchanged.
- How it is used
- Bridges logging and other void functions into function composition while preserving the composed value.
- How deep it goes
- Defines tap’s behavior and signature, then demonstrates intermediate logging in composed JavaScript functions.
- Examples
- Uses debug logging to inspect cleaned input, length checks, and the final validation result.
- What you can do after
- Apply it via R.tap to add diagnostic actions to a composition without altering its returned value.
Read how Functional Programming in JavaScript explains tap combinator →
Related concepts
- blockuses · A code block is a grouped region of code treated as a unit, with boundaries and scope or execution behavior determined by its language or context.
- functionuses · A function is a callable program unit that performs an operation, may accept inputs, and can produce a result or side effect.
- combinatorkind of · A combinator is a function or computational construct that combines, composes, or transforms smaller functions or computations into a larger operation.
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