This library is a collection of well tested utility functions that is used in many projects across Bhoos (both server and mobile).

Note that because it is to beused in mobile (i.e. react native) applications you are restricted from using fs or any other server only package.

Utility functions with a functional programming flavour

• partition : partition a list into two using a predicate
• removeDuplicates: remove duplicate entries from a list
• topologicalSort : find topological sort of a graph (represented as a list of all nodes, and a function that returns children nodes of a given node)

Creating a Normalized object from an array allows efficient lookups by id, and also gives other utility methods.

const normalized = Normalized<string>([{id: 'a', val:'obj1'}, {id:'b', val:'obj2'}]) normalized.get('a').val // => 'obj1'

Other utility methods given by Normalized is:

• filter
• getAt
• replace
• concat

Normalized can be serialized a string and recovered as follows:

Normalized.fromObj(JSON.parse(JSON.stringify(normalized))) // => normalized

String manipulation

• prefixp : check a string for a given prefix. p stands for predicate (i.e. functions that return boolean)
• removePrefix: remove a prefix from string if possible otherwise return undefined

Trim number to a max 4 digits with decimal place inbetween and suffixed by 'K', 'M', 'B', 'T' values.

trimNumber(number: number)

Return a number with ordinal suffix added.

addOrdinal(21) // => '21st'

Format a number by adding commas with trailing zeros

formatNumber(10000, 2) // => "10,000.00"

Convert utf-8 source string to an optimized uint8 (binary) array.

strToUint8(source: string)

Convert uint8 (binary) array created by strToUint8 to the original source string

uint8ToStr(buffer: Uint8Array)

Generate a numeric checksum value for the given input string

checksum(src: string): number

A Fisher-Yates algorithm based array shuffler.

Performs an in-place shuffling and returns the same input array.

shuffle<T>(array: T[]): T[]

array: An array of any type

Promise that resolve after n milliseconds

await delay(1000); // waits for 1 seconds

Memoise a function

• Write tests for the utilities you add. See any of the __tests__/*.spec.ts file for example.
• Also, run yarn coverage and ensure that you have 100% coverage on the code you add.