collection-query

A collection processing library.

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Feature

• Simple to use.
• The entity which represent the collection is close to the native object.
• Methods are few and common.

Install

npm install collection-query

Usage

import { take } from "collection-query/pull";

// Create a pull stream
const s = function* () {
  let count = 0;
  while (true) {
    yield count++;
  }
};

// Convert the stream to another
const new_s = take(3)(s);

// Each the pull stream
for (const x of new_s()) {
  console.log(x);
}


// Print 0 1 2

Pull and push

Pull and push are inspired by rxjs.

There are 2 ways to generate data.

• pull data: Produced passively, consumed actively
• push data: Produced actively, consumed passively

collection-query provides 4 streams to implement the pull and push respectively.

"pull", "async-pull", "push", "async-push"

Pull

The streams pull and async-pull base on javascript generator.

const pull_stream = function* () {
  yield 0;
};

Pull stream always generates data synchronously.

const async_pull_stream = async function* () {
  yield 0;
};

Async pull stream always generates data asynchronously.

Push

The streams push and async-push base on Emitter

const push_stream = create(function (emit) {
  emit(EmitType.Next, 0);
  emit(EmitType.Complete);
});

Push stream can generate data synchronously or asynchronously.

const async_push_stream = create_async(function (emit) {
  emit(EmitType.Next, 0);
  emit(EmitType.Complete);
});

Async push stream always generates data asynchronously.

Method

collection-query provides different set of methods to access the stream, but they almost always have the same name and the same semantics.

import * as pull from "collection-query/pull";
import * as asyncPull from "collection-query/async-pull";
import * as push from "collection-query/push";
import * as asyncPush from "collection-query/async-push";

// For example, they all have a "take" method.

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