lexeek

Making chained API Calls using @ngrx/Effects

Purpose

This recipe is useful for cooking up chained API calls as a result of a single action.

Description

In the below example, a single action called POST_REPO is dispatched and it's intention is to create a new repostiory on GitHub then update the README with new data after it is created.
For this to happen there are 4 API calls necessary to the GitHub API:

POST a new repostiry
GET the master branch of the new repository
GET the files on the master branch

	<div class="container">
	<div class="panzoom">
	<div class="diagram">
	<div id="i0" class="item">Root!</div>
	<div id="i1" class="item">Child 1</div>
	<div id="i11" class="item">Child 1.1</div>
	<div id="i12" class="item">Child 1.2</div>
	<div id="i2" class="item">Child 2</div>
	<div id="i21" class="item">Child 2.1</div>
	<div id="i3" class="item">Child 3</div>

	<!DOCTYPE html>
	<html>
	<head>
	<title>Simple Stack</title>
	<script src="http://d3js.org/d3.v2.js"></script>
	<style>
	svg {
	border: solid 1px #ccc;
	font: 10px sans-serif;
	shape-rendering: crispEdges;

	import * as admin from 'firebase-admin';

	import { Change, EventContext } from 'firebase-functions';
	import { isEqual } from 'lodash';
	import DocumentSnapshot = admin.firestore.DocumentSnapshot;
	import FieldPath = admin.firestore.FieldPath;

	const isEquivalent = (before: any, after: any) => {
	return before && typeof before.isEqual === 'function'
	? before.isEqual(after)

	/**
	* Get the caret position in all cases
	*
	* @returns {object} left, top distance in pixels
	*/
	getCaretTopPoint () {
	const sel = document.getSelection()
	const r = sel.getRangeAt(0)
	let rect
	let r2

	<div class="container">
	<div class="panzoom">
	<div class="diagram">
	<div id="i0" class="item">Root!</div>
	<div id="i1" class="item">Child 1</div>
	<div id="i11" class="item">Child 1.1</div>
	<div id="i12" class="item">Child 1.2</div>
	<div id="i2" class="item">Child 2</div>
	<div id="i21" class="item">Child 2.1</div>
	<div id="i3" class="item">Child 3</div>

	@Effect({dispatch: false})
	entityCreationSuccess$: Observable<Action> = this.actions$.pipe(
	ofType(UserActions.CREATE_USER_SUCCESS, PostActions.CREATE_POST_SUCCESS),
	tap(action => {
	this.router.navigate(['../'], {relativeTo: this.route})
	})
	);

	import {
	Injectable,
	Injector,
	ComponentFactoryResolver,
	EmbeddedViewRef,
	ApplicationRef
	} from '@angular/core';

	@Injectable()
	export class DomService {

	import { Action, ActionReducer, Store } from '@ngrx/store';
	import { BehaviorSubject } from 'rxjs/BehaviorSubject';
	import { Observable } from 'rxjs/Observable';
	import { map } from 'rxjs/operator/map';
	import { Observer } from 'rxjs/Observer';

	// TODO: How to initialize those variables?
	const dispatcherMock: Observer<Action>,
	reducerMock: Observer<ActionReducer<any>>,
	stateMock: Observable<any>;

	# Shorthand Git CLI syntax + better git log

	# Better git log
	git config --global alias.lg "log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --date=relative"

	function gs {
	git status
	}

	function gd {