async-ray

Async-Ray

Purpose of this package is to provide async/await callbacks forfilter, find, forEach, map, reduce methods in Array.

Basic usage

const { AsyncRay } = require('async-ray');

.aFilter

.aFilter(async callback(element[, index[, array]]))

async function dummy(element, needle) {
  return Promise.resolve(element > needle);
}

const inputArray = [1, 2, 3, 4];

// Call filter method
const filterArray = await AsyncRay(inputArray).aFilter(
  async (i, index, collection) => {
    // Dummy async function
    return await dummy(i, 2);
  }
);

console.log(filterArray);
// Output is [3, 4]

.aFind

.aFind(async callback(element[, index[, array]]))

Find will return the found value or undefined

async function dummy(element, needle) {
  return Promise.resolve(element === needle);
}

const inputArray = [1, 2, 3, 4];

// Call Find method
const outputElement = await AsyncRay(inputArray).aFind(
  async (i, index, collection) => {
    return await dummy(i, 2);
  }
);

console.log('Output is ', outputElement);
// Output is 2

.aForEach

.aForEach(async callback(element[, index[, array]]))

async function dummy(element) {
  return Promise.resolve(element);
}

const inputArray = [1, 2, 3, 4];
const outputArray = [];

// Call ForEach method
await AsyncRay(inputArray).aForEach(async (i, index, collection) => {
  outputArray.push(await dummy(i));
});

console.log('Output is ', outputArray);
// Output is [1, 2, 3, 4]

.aMap

.aMap(async callback(element[, index[, array]]))

async function dummy(element) {
  return Promise.resolve(element);
}

const inputArray = [1, 2, 3, 4];

// Call Map method
const mappedArray = await AsyncRay(inputArray).aMap(
  async (i, index, collection) => {
    // Dummy async function
    return await dummy(i);
  }
);
console.log(mappedArray);
// Output is [1, 2, 3, 4]

.aReduce

.aReduce(async callback(accumulator, element[, index[, array]]), [initialValueOptional])

async function dummy(element) {
  return Promise.resolve(element);
}

const inputArray = [10, 20, 30, 40];

// Call reduce method
const output = await AsyncRay(inputArray).aReduce(
  async (acc, i, index, collection) => {
    return acc + (await dummy(i));
  },
  1
);

console.log('Output is ', output);
// Output is 101

Chaining methods

Please note that, .aFilter, .aFind, .aForEach, .aMap and aReduce cannot be chained with each other.

Eg:

// Below code will throw an error
AsyncRay([1,2,3]).aMap(...).aReduce(...)

But .aFilter, .aFind, .aForEach, .aMap and aReduce can be chained with other Array methods.

sample 1 - aMap and filter

async function dummy(ele) {
  return Promise.resolve(ele);
}

const inputArray = [1, 2, 3, 4];

const chainedValue = (await AsyncRay(inputArray).aMap(
  async (ele) => await dummy(ele * 10)
)).filter((ele) => ele > 20);

console.log('Output is ', chainedValue);
// Output is [30, 40]

sample 2 - aMap and find

async function dummy(ele) {
  return Promise.resolve(ele);
}

const inputArray = [1, 2, 3, 4];

const chainedValue = (await AsyncRay(inputArray).aMap(
  async (ele) => await dummy(ele * 10)
)).find((ele) => ele === 20);

console.log('Output is ', chainedValue);
// Output is 20

sample 3 - aMap and reduce

async function dummy(ele) {
  return Promise.resolve(ele);
}

const inputArray = [1, 2, 3, 4];

const chainedValue = (await AsyncRay(inputArray).aMap(
  async (ele) => await dummy(ele * 10)
)).reduce((acc, ele) => acc + ele), 1);

console.log('Output is ', chainedValue);
// Output is 101