mapx

mapx provides generic helpers for working with Go maps in a clear and reusable way.

It is designed to help you replace repetitive map loops with small functions for:

• extracting keys and values
• checking for key presence
• transforming maps into other shapes
• filtering and partitioning entries
• combining, inverting, or counting entries

Overview

Use mapx when you want map logic to be easier to read, reuse, and test.

It is especially useful when:

• the same map loop appears in multiple places
• a helper makes the intent of the code clearer
• you want type-safe generic utilities instead of custom one-off helpers

When to use it

Use mapx when:

• you need a common map operation expressed clearly
• you want to avoid repeating small loops throughout the codebase
• you prefer reusable generic helpers over ad hoc implementations

Prefer a simpler local loop when:

• the operation is tiny and only used once
• a helper would make the code less obvious
• performance or allocation behavior needs a specialized implementation

API reference

Extract keys or values

Function	Purpose
Keys	Returns all keys from a map
Values	Returns all values from a map
UniqueValues	Returns only unique values from a map
SortedKeys	Returns keys in ascending sorted order (ordered types only)
SortedKeysByFunc	Returns keys sorted by a custom comparison function

Look up or check entries

Function	Purpose
Contains	Returns true if the map contains all of the specified keys
ValueOr	Returns the value for a key, or a fallback if the key is absent

Transform or reshape data

Function	Purpose
ToSlice	Converts a map into a slice using a mapper function
MapKeys	Returns a new map with each key transformed by a mapper function
MapValues	Returns a new map with each value transformed by a mapper function
Invert	Swaps map keys and values
Combine	Merges multiple maps into one; last writer wins on key conflict
Merge	Merges two maps into one using a resolver function to handle key conflicts

Filter, partition, or visit entries

Function	Purpose
Filter	Returns a map containing only entries that satisfy a predicate
Any	Returns true if any entry satisfies a predicate
All	Returns true if every entry satisfies a predicate; true for empty
Partition	Splits a map into two based on a predicate
Count	Returns the number of entries whose value equals a candidate
CountBy	Returns a map of counts grouped by the result of a classifier
Apply	Runs a function on each map entry for side effects

Notes

• Prefer the function that most clearly expresses your intent.
• Prefer the simplest helper that matches the operation.
• Map iteration order is not guaranteed; keep this in mind when ordering matters in your calling code.
• Check each function's documentation for details such as key-conflict behavior and zero-value handling.

Examples

• Examples
• Unit tests