feat: docs api design

pkg/tools/generics.go

@@ -0,0 +1,65 @@
+package tools
+
+// Map returns a new slice where each element is the result of fn for the corresponding element in the original slice
+func Map[T any, U any](slice []T, fn func(T) U) []U {
+	result := make([]U, len(slice))
+	for i, t := range slice {
+		result[i] = fn(t)
+	}
+
+	return result
+}
+
+// Contains returns true if find appears in slice
+func Contains[T comparable](slice []T, find T) bool {
+	for _, t := range slice {
+		if t == find {
+			return true
+		}
+	}
+
+	return false
+}
+
+// IndexOf returns the index of find if it appears in slice. If find is not in slice, -1 will be returned.
+func IndexOf[T comparable](slice []T, find T) int {
+	for i, t := range slice {
+		if t == find {
+			return i
+		}
+	}
+
+	return -1
+}
+
+// GroupBy returns a map that is keyed by keySelector and contains a slice of elements returned by valSelector
+func GroupBy[T any, K comparable, V any](slice []T, keySelector func(T) K, valSelector func(T) V) map[K][]V {
+	grouping := make(map[K][]V)
+	for _, t := range slice {
+		key := keySelector(t)
+		grouping[key] = append(grouping[key], valSelector(t))
+	}
+
+	return grouping
+}
+
+// ToSet returns a map keyed by keySelector and contains a value of an empty struct
+func ToSet[T any, K comparable](slice []T, keySelector func(T) K) *Set[K] {
+	set := NewSetWithCapacity[K](len(slice))
+	for _, t := range slice {
+		set.Add(keySelector(t))
+	}
+
+	return set
+}
+
+// ToMap return a map that is keyed keySelector and has the value of valSelector for each element in slice.
+// If multiple elements return the same key the element that appears later in slice will be chosen.
+func ToMap[T any, K comparable, V any](slice []T, keySelector func(T) K, valSelector func(T) V) map[K]V {
+	m := make(map[K]V)
+	for _, t := range slice {
+		m[keySelector(t)] = valSelector(t)
+	}
+
+	return m
+}