:zap: zap

Zap is a lodash inspired library.

:warning: Under development - APIs will change. :warning:

Installation

Add this to your application's shard.yml and run shards install (or crystal deps install):

dependencies:
  zap:
    github: stepanvanzuriak/zap

Usage

require "zap"

array = [] of Zap.flatten_type([1, [2, ['a', 'b']]]) # [] of Int32 | Char
Zap.chunk(['a', 'b', 'c', 4], 2) # [['a', 'b'], ['c', 4]]

Methods

Array

chunk

chunk(array, size)

Creates an array of elements split into groups the length of size

Zap.chunk(['a', 'b', 'c', 4], 2) # [['a', 'b'], ['c', 4]]

compact

compact(array)

Creates an array with all falsey values removed

Zap.compact(["a", nil, "b", nil, "c", nil]) # ["a", "b", "c"]

concat

:warning: Broken

concat(array, *values)

Creates a new array concatenating array with any additional arrays and/or values

Zap.concat([1, 2], 2, [3], [[4]], [[[4]]]) # [1, 2, 2, 3, [4], [[4]]]

drop

drop(array, number = 1)

Creates a slice of array with n elements dropped from the beginning

Zap.drop([1, 2, 3], 2) # [3]
Zap.drop([1, 2, 3], 5) # [] of Int32

drop_right

drop_right(array, number = 1)

Creates a slice of array with n elements dropped from the end

Zap.drop_right([1, 2, 3], 2) # [1]
Zap.drop_right([1, 2, 3], 5) # [] of Int32

fill

fill(array, value, start_index = 0, end_index = array.size + 1)

Fills elements of array with value from start up to, but not including, end

Zap.fill([1, 2, 3], 'a')           # ['a', 'a', 'a']
Zap.fill([4, 6, 8, 10], '*', 1, 3) # [4, '*', '*', 10]

filter

filter(array, func)

The filter method creates a new array with all elements that pass the test implemented by the provided function

Zap.filter([1, 2, 3], ->(element : Int32, index : Int32) { element > 2 }) # [3]
Zap.filter([1, 2, 3], ->(element : Int32, index : Int32) { element > 3 }) # [] of Int32

flatten

:warning: Broken

flatten(array)

Flattens array a single level deep

Zap.flatten([1, [2]])      # [1, 2]
Zap.flatten([1, [2, 3]])   # [1, 2, 3])
Zap.flatten([1, [[2, 3]]]) # [1, [2, 3]])

for_each

for_each(array, func)

Iterates over elements of collection and invokes function for each element

Zap.for_each([1, 2, 3], ->(element: Int32, index: Int32) { puts element }) # Prints 1, 2, 3

from_pairs

from_pairs(pairs)

Compres arrays of pairs to Hash

Zap.from_pairs([['a', 1], ['b', 2]]) # {'a' => 1, 'b' => 2}

head

head(array)

Gets the first element of array

Zap.head([1, 2, 3])   # 1
Zap.head([] of Int32) # Nil

index_of

index_of(array, value, start_index = 0)

Gets the index at which the first occurrence of value is found in array

Zap.index_of([1, 2, 1, 2], 2)    # 1
Zap.index_of([3], 2)             # -1
Zap.index_of([1, 2, 1, 2], 2, 2) # 3
Zap.index_of([1, 2, 2, 2], 2, 2) # 2

intersection

intersection(*values)

Creates an array of unique values that are included in all given arrays

Zap.intersection([1, 2, 3], [1, 2])           # [1, 2]
Zap.intersection([1, 2, 3], [1, 2], [1])      # [1]
Zap.intersection([1, 2, 3, "a"], [1, 2], [1]) # [1]

initial

initial(array)

Gets all but the last element of array

Zap.initial([1, 2, 3])   # [1, 2]
Zap.initial([] of Int32) # [] of Int32

join

join(array, separator = ',')

Converts all elements in array into a string separated by separator

Zap.join(['a', 'b', 'c'], '~')  # "a~b~c"
Zap.join(['a', 'b', 'c'], "ab") # "aabbabc"

last

last(array)

Gets the last element of array

Zap.last([1, 2, 3])   # 3
Zap.last([] of Int32) # Nil

map

map(array, func)

The map method creates a new array with the results of calling a provided function on every element in the calling array

Zap.map([1, 2, 3], ->(element : Int32, index : Int32) { element * 2 })         # [2, 4, 6]
Zap.map([1, 2, 3], ->(element : Int32, index : Int32) { element * 2 + index }) # [2, 5, 8]

nth

nth(array, index = 0)

Gets the element at index n of array. If n is negative, the nth element from the end is returned

Zap.nth(['a', 'b', 'c', 'd'], 1)  # 'b'
Zap.nth(['a', 'b', 'c', 'd'], -2) # 'c'

pull

pull(array, *values)

Removes all given values from array

Zap.pull([['a', 'b', 'c', 'a', 'b', 'c'], 'a', 'c')   # ['b', 'b']

reverse

reverse(array)

Reverses array so that the first element becomes the last, the second element becomes the second to last, and so on.

array = [1, 2, 3]

Zap.reverse(array) # [3, 2, 1]

array # [3, 2, 1]

reduce

reduce(array, func)

The reduce method applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value

Zap.reduce([1, 2, 3], -> (acc: Int32, element: Int32) {acc + element}) # 6

sorted_uniq

sorted_uniq(array)

Sort array and returns a new array by removing duplicate values in self

Zap.sorted_uniq([2, 1, 2]) # [1, 2]

tail

tail(array)

Gets all but the first element of array

Zap.tail([1, 2, 3])   # [2, 3]
Zap.tail([] of Int32) # Nil

take

take(array, start_index = 1)

Creates a slice of array with n elements taken from the beginning

Zap.take([1, 2, 3])    # [1]
Zap.take([1, 2, 3], 2) # [1, 2]
Zap.take([1, 2, 3], 5) # [1, 2, 3])
Zap.take([1, 2, 3], 0) # [] of Int32

sample

sample(array)

Gets a random element from array

Zap.sample([1, 2]) # 1 or 2
Zap.sample([1])    # 1

shuffle

shuffle(array)

Creates an array of shuffled values

Zap.shuffle([2]) # [2]
Zap.shuffle([1, 2]) # [1, 2] or [2, 1]

union

union(*values)

Creates an array of unique values

Zap.union([2], [1, 2])        # [2, 1]
Zap.union([2], [1, 2], ["a"]) # [2, 1, "a"]

without

without(array, *values)

Creates an array excluding all given values

Zap.without([1, 2, 3], 1, 2) # [3]

xor

xor(*values)

Creates an array of unique values that is the symmetric difference of the given arrays

Zap.xor([2, 1], [2, 3]) # [1, 3]
Zap.xor([2, 1], [2, 3], [1]) # [3]

zip

zip(*values)

Creates an array of grouped elements, the first of which contains the first elements of the given arrays, the second of which contains the second elements of the given arrays, and so on

Zap.zip([1, 2], [11, 22], [111, 222, 333])                # [[1, 11, 111], [2, 22, 222]]
Zap.zip([] of Int32)                                      # [] of Int32)
Zap.zip(['a', 'b'], [1, 2], [true, false], [true, false]) # [['a', 1, true, true], ['b', 2, false, false]]

Util

flatten_type

flatten_type(object)

Recursively flattens types

Zap.flatten_type(1)                    # Int32
Zap.flatten_type([1, [2]])             # Int32
Zap.flatten_type([1, [2, ['a', 'b']]]) # Int32 | Char

Contributing

  1. Fork it (https://github.com/stepanvanzuriak/zap/fork)
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

Contributors

stepanvanzuriak - creator, maintainer