pine 🍍
Utility library for deno with an FP bent.
You should be able to pull all functions straight from mod like import { take } from "https://deno.land/x/pine/mod.ts"
I highly recommend looking at the test file for a function to see how to use it.
stability
Most of the api should be pretty stable, but for now I would pin a version as I am planning to rewrite some of the function implementations, and add things like automatic currying.
functions implemented so far:
add
add(x: number, y: number): number
Returns the numbers added together
add(2, 3) == 5
chunkEvery
chunkEvery<T>(count: number, list: T[]): T[][]
Chunks the list by count excess are thrown away
`chunkEvery(2, [1, 2, 3, 4, 5]) == [[1, 2], [3, 4]]
clamp
clamp(min: number, max: number, value: number): number
clamp(0, 10, 20) == 10
dec
dec(n: number): number
Returns one less than n
dec(3) == 2
enumerate
enumerate<T>(list: T[]): [number, T] []
Returns an array of tuples having the signature [index, item]
enumerate(['a', 'b', 'c']) == [[0, 'a'], [1, 'b'], [2, 'c']]
f
f(): boolean
Returns false
f() == false
filter
filter<T>(pred: (T) => bool, list: T[]): T[]
Returns all items in the list where T satisfies pred
filter(isEven, [1, 2, 3, 4]) == [2, 4]
first
first<T>(list: T[]): T[]
Returns all items in the array except the last one
first([1, 2, 3]) == [1, 2]
flip
flip(fn: Function): Function
Takes a function with two parameters
Returns the function with the arguments reversed
fold
fold<T, U>(fn: (acc: U, x: T) => U, acc: U, list: T[]): U
Takes a reducer, an initial accumulator value, and a list of items. Applies the function on the accumulator, and each item of the list as it iterates through and returns the final accumulator.
fold(add, 0, [1, 2, 3]) == 6
frequencies
frequencies<T>(list: <T>): Map<T, number>
Returns a frequency table created from the list, in a Map data structure
frequencies([1, 1, 2, 2, 2], Map{ 1: 2, 2: 3})
hasKey
hasKey(key: keyof any, obj: Object): boolean
Returns wether the object has the given key
hasKey("x", {x: 1}) == true
head
head<T>(list: T[]): T
Returns the first item in a list
head([1, 2, 3]) == 1
identity
`identity(item: T): T1
Returns the item passed in
identity(5) == 5
inc
inc(n: number): number
Returns one higher than n
inc(1) == 2
indexMap
indexMap<T, U>(fn: (i: number, item: T) => U, list: T[]): U
Runs a function for every item in the list supplying the index, and the item as arguments
indexMap((i, item) => i + item, [5, 5, 5]) == [5, 6, 7]
isEmpty
isEmpty<T>(list: T[]): boolean
Returns wether the given list is empty
isEmpty([]) == true
isEven
isEven(n: number): boolean
Returns wether the given number is even
isEven(2) == true
isOdd
isOdd(n: number): boolean
Returns wether the given number is odd
isOdd(3) == true
last
last<T>(list: T[]): T
Returns the last item in a list
last([1, 3, 2]) == 2
length
length<T>(list: T[]): number
Returns the length of the list
length([1, 1, 1]) == 3
map
map<T, U>(fn: T => U, list: T[]): U
Applies a function to each item in a list, returning a new list of the results of each call
mapGet
mapGet<K, V>(key: K, map: Map<K, V>): V
Returns the value for the key key on the map. Throws an error if the key is not found
mapHas
mapHas<K, V>(key: K, map: Map<K, V>): boolean
Returns whether a map has the given key
mapSet
mapSet<K, V>(key: K, value: V, Map<K, V>): Map<K, V>
Returns a new map based off the one passed in with the key key set to value
max
max(x: number, y: number): number
Returns the larger of two numbers
max(2, 4) == 4
maximum
max(list: number[]): number
Returns the largest item in the list
maximum([1, 2, 3]) = 3
min
min(x: number, y: number): number
Returns the smaller of two numbers
min(2, 4) == 2
minBy
`minBy(fn: (item: T) => T, x: T, y: T): T
Returns the smaller of originals from applying the function to both items
const first = { x: 4 }
const second = { x: 5}
minBy(o => o.x, first, second) == firstminimum
minimum(list: number[]): number
Returns the smallest item in the list
`minimum([1, 2, 3]) == 1
not
not(b: boolean): boolean
Returns the opposite of the applied boolean
not(true) == false
range
range(start: number, stop: number): number[]
Returns an array of numbers from start to stop inclusive
range(1, 3) == [1, 2, 3]
reduce
reduce<T>(fn: (x: T, y: T) => T, list: T[]): T
Shorthand for call to fold where the initial value is the first item of the list, and iterates through the rest of the list
reduce(add, [1, 2, 3]) == 6
repeat
repeat<T>(count: number, item: T): T[]
Returns an array of count length with item repeated
`repeat(3, “apple”) == [“apple”, “apple”, “apple”]
reverse
reverse<T>(list: T[]): T[]
Returns the list in the reversed order
reverse([1, 2, 3]) == [3, 2, 1]
scan
scan<T, U>(fn: (x: T) => U, init: U, list: T[]): U[]
Iterates over the list in the same way as fold, but saves all steps along the way.
scan(add, 0, [1, 2, 3]) == [0, 1, 3, 6]
t
t(): boolean
Returns true
t() == true
tail
tail<T>(list: T[]); T[]
Returns all items after the first in a list
tail([1, 2, 3]) == [2, 3]
take
take<T>(count: number, list: T[]): T[]
Returns the first count items from a list
take(2, [1, 2, 3, 4, 5]) == [1, 2]
takeLast
takeLast<T>(count: number, list: T[]): T[]
Returns the last count items from a list
takeLast(2, [1, 2, 3, 4, 5]) == [4, 5]
takeWhile
takeWhile<T>(pred: (T) => boolean, list: T[]): T[]
Returns elements of the list until it first gets a false value from the predicate. Does not return the value that returned false
takeWhile(x => x < 2, [1, 1, 1, 3]) == [1, 1, 1]
zip
zip<T, U>(first: T[], second: U[]): [T, U][]
Zips two arrays together into an array of tuples. Extra items from the longer will be ignored
zip([1, 2, 3, 4], ["a", "b", "c"]) == [[1, "a"], [2, "b"], [3, "c"]]
TODO:
- more tests
- automatic currying
- Option/Result types
- more tests
- more tests
- better way to handle type of functions
Contribute?
Want to send a pr? I’m pretty open. If you’re adding a new function, it needs to do three things:
- be in a new file
- have a matching test file
- export from mod