ts-utls

ts-utls is a small TypeScript library where I put all the useful stuff I regularly need in my projects.
Feel free to use it at your discretion with the apppropriate credit mentions.

NB: I've developed the same kind of libraries for both Go and Python.

Usage

npm i ts-utls

This library contains the following functions:

• For arrays:
  • chunk: split an array into chunks of a maximum size;
  • flatten: transform an array of arrays of items to an array of items;
  • groupBy: group an array of items by some item's field;
  • range: return a list of integers;
• For bits and buffers:
  • buffer2BytesString: transform a byte array to its string representation of byte(s);
  • int2Buffer: convert an integer to its byte array equivalent;
  • splitBuffer: split a byte array using a passed byte array;
  • stringBytes2Buffer: transform a string representing one or more bytes to a byte array;
• For JSON:
  • ConvertJSON.toClass: allows casting a JSON string to the targeted class instance;
• For numbers:
  • euclideanDivision: compute the euclidean division of two integers, returning the quotient and the remainder;
• For strings:
  • capitalize: capitalize the first letter of a sentence;
  • fromHex and toHex: transform hexadecimal string representation to byte array, and vice-versa;
  • hashCode: compute the equivalent of Java's hashCode;
  • reverse: reverse the order of characters;
  • shuffle: randomly shuffle the characters;
  • splitCamelCaseWords: put a space between each "word" found in a camel-case string;
  • xor: apply the XOR logical function to two strings in the sense that each charCode is xored;
• For time:
  • currentTimestampMillis: return the current Unix timestamp in milliseconds;
  • sleep: hold the current thread for a while;
  • toMySQLDateOrEmpty: transform any date string to a MySQL-compatible date for SQL statement.

It also contains an extremely simplified version of Either, List and Maybe monads.
These latter implementations are heavily inspired by the monet library which I had to decouple in my work due to incompatibilities with TypeScript versions higher than 4.7, hence the creation of these monads.
However, they probably should still be challenged.

eg.

import {
  buffer2BytesString, capitalize, chunk, ConvertJSON, currentTimestampMillis, Either, euclideanDivision, flatten, fromHex, groupBy, hashCode, int2Buffer, List, Maybe, None, range, reverse, shuffle, sleep, Some, splitCamelCaseWords, splitBuffer, stringBytes2Buffer, Right, toHex, toMySQLDateOrEmpty, xor
} from 'ts-utls'

// For arrays

const arr = [1, 2, 3, 4, 5]
const chunked = chunk(arr, 2)
// [[1, 2], [3, 4], [5]]
console.log(chunked)

const arrs = [[1, 2], [3, 4], [5]]
const flattened = flatten(arrs)
// [1, 2, 3, 4, 5]
console.log(flattened)

const arr = [{ field1: '1', field2: 1 }, { field1: '1', field2: 2 }, { field1: '3', field2: 3 }]
const grouped = groupBy(arr, 'field1')
console.assert(grouped['1'].length === 2)

const firstFive = range(0, 5)
// [0, 1, 2, 3, 4]
console.log(firstFive)
const evenBefore10 = range(0, 10, 2)
// [0, 2, 4, 5, 6, 8]
console.log(evenBefore10)

// For bits and buffers

const buf0 = Buffer.from([0, 1, 128, 2, 3])
const delimiter = Buffer.from([128])
const splitsWithout = splitBuffer(buf0, delimiter, false)
// [[0, 1], [2, 3]]
console.log(splitsWithout)
const splitsWith = splitBuffer(buf0, delimiter, true)
// [[0, 1], [128], [2, 3]]
console.log(splitsWith)

const buf1 = int2Buffer(1)
console.assert(buf1[0] === 1)

const str = '11011010'
const buf2 = stringBytes2Buffer(str)
console.assert(buf1[0] === 218)
const str2 = buffer2BytesString(buf2)
console.assert(str === str2)

// For JSON

const myClass = ConvertJSON(jsonStr).toClass(MyClass)
assert(myClass instanceof MyClass)

// For numbers

const n = 15, d = 2
const [q, r] = euclideanDivision(n, d)
console.assert(q === 7 && r === 1)

// For strings

const phrase = capitalize('my sentence is capitalized')
console.assert(phrase === 'My sentence is capitalized')

const h = hashCode('Hello')
console.assert(h === 69609650)

const hexStrings = ['ff']
const buffers = hexStrings.map(fromHex)
const strings = buffers.map(toHex)
console.assert(hexStrings[0] === strings[0])

const toReverse = 'abcd'
const reversed = reverse(toReverse)
console.assert(reversed === 'dcba')

const str = 'abcd'
const shuffled = shuffle(str)
console.assert(str.length === shuffled.length)
console.assert(str !== shuffled)

const sentence = splitCamelCaseWords('myCamelCase')
console.assert(sentence === 'my Camel Case')

const a = 'a'
const b = 'b'
const xored = xor(a, b)
console.assert(xored === '\u0003')

// For time

const ts = currentTimestampMillis()
await sleep(100)
console.assert(currentTimestampMillis() > ts + 100)

const date = 'Fri Apr 8 2022 01:00:00 GMT+0200'
const mysqlDatetime = toMySQLDateOrEmpty(date, true)
console.assert(mysqlDatetime === '2022-04-08 01:00:00')

// Either

const eitherString = Either('string', true)
console.assert(eitherString.isRight())
console.assert(eitherString.right() === 'string')
const rightString = Right('right')
console.assert(rightString.equals(eitherString))

// List

const listString = List.fromArray(['a', 'b', 'c'])
console.assert(!listString.isNil)
console.assert(listString.head() === 'a')
console.assert(listString.contains('b'))
const filteredList = listString.filter(_ => _ !== 'a')
console.assert(filteredList.toArray().equals(['b', 'c']))

// Maybe

const maybeString: Maybe<string> = Some('string')
console.assert(maybeString.isSome() && !maybeString.isNone() && maybeString.some() === 'string' && maybeString.getOrElse('nothing') === 'string')
const nothing = None<string>()
console.assert(nothing.isNone() && !nothing.isSome(), nothing.getOrElse('something') === 'something')
const leftString = nothing.toEither('string')
console.assert(leftString.isLeft() && leftString.left() === 'string')

Please let me know if you have more optimized implementations of any of my stuff.

Dependencies

To run the tests, you would need to install live-server:

npm i -g live-server

NB: Tests use port 10001, beware if any other process is running on that port as such a conflict may disable them.

License

This library is distributed under a MIT license.
See the LICENSE file.