@mrpelz/misc-utils

Miscellaneous TypeScript helpers.

data

Miscellaneous data conversion helpers.

emptyBuffer

Empty/zero-length Buffer.

falseBuffer

One-byte 0 Buffer.

trueBuffer

One-byte 1 Buffer.

arrayCompare

const arrayCompare = <
  A extends Array<unknown>,
  B extends Array<unknown>,
>(
  a: A,
  b: B,
): b is B

Returns true if all elements of array a strict-equal array b.

arrayPadLeft

const arrayPadLeft = <T>(
  input: T[],
  length: number,
  value: T = null as unknown as T,
): T[]

Inserts length-n of value at the start of array input.
Modifies array in-place and returns it.

arrayPadRight

const arrayPadRight = <T>(
  input: T[],
  length: number,
  value: T = null as unknown as T,
): T[]

Inserts length-n of value at the end of array input.
Modifies array in-place and returns it.

bufferChunks

const bufferChunks = (input: Buffer, chunkSize = 1): Buffer[]

Splits Buffer input into chunks of size chunkSize each.
Returns array of Buffer chunks. Throws if input Buffer is smaller than chunkSize.

concatBytes

const concatBytes = (input: number[]): Buffer

Concatenates number-array as bytes and returns as Buffer.

humanPayload

const humanPayload = (input: Buffer): string

Pretty-prints Buffer input’s binary contents in a human readable format, represented as binary, decimal and hexadecimal:

0b00000000 | 0b00000001 | 0b00000010 | 0b00001111 | 0b00010000
         0 |          1 |          2 |         15 |         16
      0x00 |       0x01 |       0x02 |       0x0f |       0x10

Returns pre-formatted multi-line string.

jsonParseGuarded

const jsonParseGuarded = <T>(input: unknown): T | Error

Guarded JSON-parse. Tries to parse anything in input, returns JSON.parse result. Returns Error if input is not a string. If parsing of the string fails, catches the Error and returns it. Error is returned instead of thrown to ease implementation of fallback code paths.

numberToDigits

const numberToDigits = (
  input: number,
  pad = 0,
  radix = 10,
): number[]

Splits number in input into single digits and returns them as number-array. Throws if input is not an integer.

readNumber

const readNumber = (input: Buffer, bytes = 1): number

Read number value from Buffer input with number of bytes. Throws if the buffer isn’t long enough to fit the desired byte count.

• bytes = 1 → UInt8
• bytes = 2 → UInt16LE
• bytes = 4 → UInt32LE

Throws otherwise.

booleanToBuffer

const booleanToBuffer = (input: boolean): Buffer

Turns boolean input into trueBuffer or falseBuffer respectively.

bufferToBoolean

const bufferToBoolean = (input: Buffer): boolean

Turns Buffer input into boolean. A buffer whose first byte is zero is considered false, everything else is considered true. Throws if Buffer isn’t long enough.

swapByte

const swapByte = (input: number): number

Bitwise-invert the the input value. Use for single byte values.

writeNumber

const writeNumber = (input: number, bytes = 1): Buffer

Write number value from input with number of bytes into Buffer. Throws if the number cannot be represented using the desired byte count.

• bytes = 1 → UInt8
• bytes = 2 → UInt16LE
• bytes = 4 → UInt32LE

Throws otherwise.

number

bitRange

const bitRange = (count: number): number

Returns the number bit range of given bit length in count, e.g.

• 4 → 15
• 8 → 255
• 16 → 65535

byteRange

const byteRange = (count: number): number

Returns the number range of given byte length in count, e.g. 4 → 4294967295.