util

Documentation

Overview

util contains small standalone utility functions. This should have no dependencies on other server packages.

Index

• func CloneMapNonNil[M ~map[K]V, K comparable, V any](m M) M
• func Coalesce[T comparable](vals ...T) T
• func FilterSlice[T any](in []T, predicate func(T) bool) []T
• func FoldSlice[T any, A any](in []T, initializer A, reducer func(A, T) A) A
• func InverseMap[M ~map[K]V, K, V comparable](m M) map[V]K
• func MapConcurrent[IN any, OUT any](input []IN, mapper func(IN) (OUT, error)) ([]OUT, error)
• func MapSlice[T, S any](xs []T, f func(T) S) []S
• func MaxTime(a, b time.Time) time.Time
• func MinTime(a, b time.Time) time.Time
• func RepeatSlice[T any](xs []T, n int) []T
• func SliceHead[S ~[]E, E any](s S, n int) S
• func SliceTail[S ~[]E, E any](s S, n int) S
• func SortSlice[S ~[]E, E constraints.Ordered](slice S)

Functions

func CloneMapNonNil

func CloneMapNonNil[M ~map[K]V, K comparable, V any](m M) M

CloneMapNonNil is like maps.Clone except it can't return nil, it will return an empty map instead.

func Coalesce

func Coalesce[T comparable](vals ...T) T

Coalesce returns the first non-zero value of its arguments, or the zero value for the type if all are zero.

func FilterSlice

func FilterSlice[T any](in []T, predicate func(T) bool) []T

FilterSlice iterates over elements of a slice, returning a new slice of all elements predicate returns true for.

func FoldSlice

func FoldSlice[T any, A any](in []T, initializer A, reducer func(A, T) A) A

FoldSlice folds left a slice using given reducer function and initial value.

func InverseMap

func InverseMap[M ~map[K]V, K, V comparable](m M) map[V]K

InverseMap creates the inverse map, ie., for a key-value map, it builds the value-key map.

func MapConcurrent

func MapConcurrent[IN any, OUT any](input []IN, mapper func(IN) (OUT, error)) ([]OUT, error)

MapConcurrent concurrently maps a function over input and fails fast on error.

func MapSlice

func MapSlice[T, S any](xs []T, f func(T) S) []S

MapSlice given slice xs []T and f(T) S produces slice []S by applying f to every element of xs

func MaxTime

func MaxTime(a, b time.Time) time.Time

MaxTime returns the later of two given time.Time

func MinTime

func MinTime(a, b time.Time) time.Time

MinTime returns the earlier of two given time.Time

func RepeatSlice

func RepeatSlice[T any](xs []T, n int) []T

RepeatSlice given slice and a number (n) produces a new slice containing original slice n times if n is non-positive will produce nil

func SliceHead

func SliceHead[S ~[]E, E any](s S, n int) S

SliceHead returns the first n elements of s. n may be greater than len(s).

func SliceTail

func SliceTail[S ~[]E, E any](s S, n int) S

SliceTail returns the last n elements of s. n may be greater than len(s).

func SortSlice

func SortSlice[S ~[]E, E constraints.Ordered](slice S)

SortSlice sorts the given slice of an ordered type. Sort is not guaranteed to be stable.