@kennethober/helpers v0.0.2

Helpers

A module of helper functions.

The guiding principle of this module is to provide functions that are consistently useful, have no external dependencies, encourage good coding, and don't encourage forgetting how to use Javascript.

Installation

npm install @kennethober/helpers

Usage

// Browser
import * as H from './path/to/node_modules/@kennethober/helpers/index.js'
import { partial as p } from './path/to/node_modules/@kennethober/helpers/index.js'

// Node.js
import * as H from '@kennethober/helpers'
import { partial as p } from '@kennethober/helpers'

const add = (x, y) => x + y
const add1 = H.partial(add, 1)
const add2 = p(add, 2)

Note: if using with Node.js, import either from an .mjs file, or from a package with "type": "module" in package.json.

Development

git clone https://github.com/kennethober/helpers.git
npm install

npm run lint

npm test

npm run docs

Exported functions

Table of Contents

• partial
• partialOb
• collect
• collectUnique
• chooseN
• logTime

partial

Partially apply a function.

Parameters

• fn function Function to partially apply.
• args ...any Arguments to apply.

Returns function Function with the provided arguments applied.

partialOb

Like partial(), but partially apply a function with a the properties of a single options-object.

Parameters

• fn function Function to partially apply.
• ob Object Options-object arguments to apply; individual properties will be overwritten if the same keys are later passed in a new options object to the partially applied function.

Returns function Function with the provided options-object argument applied.

collect

Collect values with the same key and return an object with a one-to-many key-value relationship.

Parameters

• keyVals Array<Array<(string | symbol), any>> Ordered pairs of key-values to reduce over.

Returns Object<(string | symbol), Array\> Object mapping keys to arrays of values.

collectUnique

Like collect(), but eliminate duplicate values (based on set behavior).

Parameters

• keyVals Array<Array<(string | symbol), any>> Ordered pairs of key-values to reduce over.

Returns Object<(string | symbol), set\> Object mapping keys to sets of unique values.

chooseN

Return N randomly chosen elements from an array.

Parameters

• n number Number of elements to choose.
• array Array Array from which to choose elements.

Returns Array Array of chosen elements.

logTime

Call a function a number of times and log the total duration to the console.

Parameters

• times number The number of times to call a given function (synchronously, with await); useful for amplifying differences in execution time between functions.
• fn function The function to call; may be synchronous or asynchronous.
• timerId string An id/label for the timer; shows up in the log. (optional, default `${Date.now()}-${Math.random()}`)

Returns undefined Function called for side-effect only.