zeroflucs generics

When writing Go code for Go 1.17 or below, we've all written more than our fair share of methods to check "does this slice contain a thing", or "give me the first item matching a predicate". This package contains a roll-up of helpers and methods, as well as generic collection types that enable a lot of this boilerplate code to be removed.

Key attributes:

• Context support for filters/mappers (Optional)
• Does not mutate input during operation.

All code is covered 100% by tests for expected behaviour. Where filters or mappers are used methods are provided with and without context support.

Aggregations

Min

Returns the minimum value from the input slice. Returns 0 if no values.

Max

Returns the maximum value from the input slice. Returns 0 if no values.

Sum

Returns the total sum of the values. Note that when handling large values, you may overflow your input type.

Error Checking

Must

Returns the first value in a pair of (T, error) if there is no error. Otherwise will panic.

Slice Operations

All / AllContext

Returns true if all items in the slice match the filter. Will return true for an empty slice as no items fail the predicate.

Any / AnyContext

Returns true if any item in the slice matches the filter.

Concatenate

Joins N slices of items together in the given order.

Contains

Returns true if the slice contains the specified value T, false otherwise. Uses standard equality operator to compare types.

DefaultIfEmpty

Given a slice, if the slice is empty or nil will create a slice of a single default item.

Filter / FilterContext

Creates a filtered set of the values in the slice, using a filter function.

First

Returns the first item of the slice, or panics if the slice is empty. Use with DefaultIfEmpty to ensure panic-free operation over lists that are potentially empty.

FirstOrDefault

Returns the first item of the slice, or if the slice is empty returns a default value.

Group

Uses a mapper function to assign input values to buckets.

Last

Returns the last item of the slice, or panics if the slice is empty. Use with DefaultIfEmpty to ensure panic-free operation over lists that are potentially empty.

LastOrDefault

Returns the last item of the slice, or a default if the slice is empty.

Map / MapContext

Runs the specified mapper over each element of the input slice, creating an output slice of a different type.

Reverse

Creates a reverse-sorted version of the input slice.

Skip

Skip the first N elements of the slice.

Take

Take the next N elements of the slice.

ToMap / ToMapContext

Converts a slice of values to Go map, using mappers for the key and values respectively.