feat: dateutils, maputils, sliceutils.

maputils/maputils.go

@@ -0,0 +1,94 @@
+// This package includes utility functions for handling and manipulating maputils.
+// It draws inspiration from JavaScript and Python and uses Go generics as a basis.
+
+package maputils
+
+// Keys - takes a map with keys K and values V, returns a slice of type K of the map's keys.
+// Note: Go maps do not preserve insertion order.
+func Keys[K comparable, V any](mapInstance map[K]V) []K {
+	keys := make([]K, len(mapInstance))
+
+	i := 0
+	for k := range mapInstance {
+		keys[i] = k
+		i++
+	}
+
+	return keys
+}
+
+// Values - takes a map with keys K and values V, returns a slice of type V of the map's values.
+// Note: Go maps do not preserve insertion order.
+func Values[K comparable, V any](mapInstance map[K]V) []V {
+	values := make([]V, len(mapInstance))
+
+	i := 0
+	for _, v := range mapInstance {
+		values[i] = v
+		i++
+	}
+
+	return values
+}
+
+// Merge - takes an arbitrary number of map instances with keys K and values V and merges them into a single map.
+// Note: merge works from left to right. If a key already exists in a previous map, its value is over-written.
+func Merge[K comparable, V any](mapInstances ...map[K]V) map[K]V {
+	var mergedMapSize int
+
+	for _, mapInstance := range mapInstances {
+		mergedMapSize += len(mapInstance)
+	}
+
+	mergedMap := make(map[K]V, mergedMapSize)
+
+	for _, mapInstance := range mapInstances {
+		for k, v := range mapInstance {
+			mergedMap[k] = v
+		}
+	}
+
+	return mergedMap
+}
+
+// ForEach - given a map with keys K and values V, executes the passed in function for each key-value pair.
+func ForEach[K comparable, V any](mapInstance map[K]V, function func(key K, value V)) {
+	for key, value := range mapInstance {
+		function(key, value)
+	}
+}
+
+// Drop - takes a map with keys K and values V, and a slice of keys K, dropping all the key-value pairs that match the keys in the slice.
+// Note: this function will modify the passed in map. To get a different object, use the Copy function to pass a copy to this function.
+func Drop[K comparable, V any](mapInstance map[K]V, keys []K) map[K]V {
+	for _, key := range keys {
+		delete(mapInstance, key)
+	}
+
+	return mapInstance
+}
+
+// Copy - takes a map with keys K and values V and returns a copy of the map.
+func Copy[K comparable, V any](mapInstance map[K]V) map[K]V {
+	mapCopy := make(map[K]V, len(mapInstance))
+
+	for key, value := range mapInstance {
+		mapCopy[key] = value
+	}
+
+	return mapCopy
+}
+
+// Filter - takes a map with keys K and values V, and executes the passed in function for each key-value pair.
+// If the filter function returns true, the key-value pair will be included in the output, otherwise it is filtered out.
+func Filter[K comparable, V any](mapInstance map[K]V, function func(key K, value V) bool) map[K]V {
+	mapCopy := make(map[K]V, len(mapInstance))
+
+	for key, value := range mapInstance {
+		if function(key, value) {
+			mapCopy[key] = value
+		}
+	}
+
+	return mapCopy
+}