keyu

Keyu (key utilities) provides flexible utilities to help you build solid projects without repeating yourself.

With this utilities you will be able to:

• Build some functional programming code.
• Work with asyncronous code like if it was syncronous*.
• Iterate objects in same way you iterate arrays.
• Apply some advanced concurrency patterns (Rob Pike).
• Convert integers, floats or json correctly and safetly.

*compose functions independently if they return promises or actual values

Utilities

Functional programming

Compose

Compose N functions, works with promises too.

const {compose} = require('keyu');

const sum1 = x => x+1;
const mult2 = x => x*2;
const dbSum = x => Promise.resolve(x+1);

const sumAndMult = compose(mult2,sum1);
const sumAndMultDB = compose(dbSum,mult2,sum1);

sumAndMult(1) // 4
sumAndMultDB(1) // Promise(5)

Pipe

Compose N functions in reverse order, works promises too.

const {pipe} = require('keyu');

const sum1 = x => x+1;
const mult2 = x => x*2;
const dbSum = x => Promise.resolve(x+1);

const sumAndMult = pipe(sum1,mult2);
const sumAndMultDB = pipe(sum1, mult2, dbSum);

sumAndMult(1) // 4
sumAndMultDB(1) // Promise(5)

Objects

Map

Maps an object based on the mapping function passed.

let obj = {a:1,b:2,c:3};

console.log(obj.map(value => value+1)) // {a:2}
console.log(obj.map((value, key) => `${key}:${value+1}`)) // {a:'a:2'}

functional programmming implementation:

const {map,compose} = require('keyu');

const sum1 = compose(map(x => x+1))

sum1([1]) // [2]
sum1({a:1}) // {a:2}

Filter

Filters an object based on the filter function passed.

let obj = {a:1,b:2,c:3};

console.log(obj.filter(value => value > 2)) // {c:3}

console.log(obj.filter((value, key) => value > 1 && key === 'c')) // {c:3}

functional programmming implementation:

const {filter,compose} = require('keyu');

const greaterThan5 = compose(filter(x => x > 5 ))

greaterThan5([1,2,3,4,5,6,7,8]) // [6,7,8]
greaterThan5({a:1,b:2,c:3,d:4,e:5,f:6,g:7}) // {f:6,g:7}

Concurrency

Promise.any

Promise.all executes an array of promises in parallel and returns all of them either they are sucessful or not without failing.

Promise.any([Promise.resolve(1),Promise.reject(2), Promise.resolve(3)]).then(console.log) // [ { value: 1 }, { error: 2 }, { value: 3 } ]

Promise.best

Promise.best execute an array of promises in parallel and returns the first one to be sucessful.

Promise.best([Promise.reject(1),Promise.resolve(2), Promise.resolve(3)]).then(console.log) // 2

Promise.best([Promise.reject(1),Promise.reject(2), Promise.reject(3)]).catch(console.log) // [1,2,3]

Conversions

jsonOr

Converts safetly any input into a json, if it fails returns the default function value.

jsonOr(33)('{"a":1}') // -> {a:1}
jsonOr(33)(null) // -> 33
jsonOr(value => 33)(null) // -> 33

floatOr

Converts safetly any input into a float, if it fails returns the default function value.

floatOr(33)('11.33') // -> 11.33
floatOr(33)(null) // -> 33
floatOr(value => 33)(null) // -> 33

intOr

Converts safetly any input into an integer, if it fails returns the default function value.

intOr(33)('11') // -> 11
intOr(33)(null) // -> 33
intOr(value => 33)(null) // -> 33

setPrecision

Set the amount of decimals for any given float safelty or returns cero precision.

setPrecision(3,'1.1234') // -> 1.234