ariesmcrae

The importance of dependency injection

Say you have a class named AbcClass.

If AbcClass depends on AnotherClass, and AnotherClass eventually needs to make a network call (e.g. to S3, Databse, GIS, some other party), then don't instantiate AnotherClass inside AbcClass. AnotherClass should be injected into the constructor of AbcClass.

Why? Here's the reason why:

Say AnotherClass is instantiated inside AbcClass. When you write a test for AbcClass, AnotherClass will inevitably make a network call.

ariesmcrae

Typescript: Find an item from one list to another

Version 1: the imperative approach

type Item = {
  id: string
  name: string
}

const items1: Item[] = [

ariesmcrae

Typescript: Basic auth (username/password) with Axios

// npm install axios

import axios, { AxiosInstance } from 'axios'

const axiosInstance: AxiosInstance = axios.create({
  baseURL: 'https://jsonplaceholder.typicode.com',
 timeout: 3000,

ariesmcrae

Typescript: Date comparison using date-fns

import { compareAsc, parseISO } from 'date-fns';

type UltraMarathoner = {
  id: string;
  name: string;
  finishTime: string;
};

ariesmcrae

Typescript: How to parse a unix epoch date using date-fns library

  // npm install date-fns date-fns-tz
  
  import { fromUnixTime, } from 'date-fns';
  import { utcToZonedTime, format as utcFormat } from 'date-fns-tz';

  // Unix epoch timestamp is a string in milliseconds in UTC
  const unixTimestampString = '1692761130000'; // 2023-08-23 03:25:30.000Z

ariesmcrae

Typescript: How to parse a UTC date using the date-fns library

Say you want to parse this date: 2023-05-31 T06:52:03Z. Note: This date is non-standard as it has a space between 31 and T

  // npm install date-fns date-fns-tz

  import { parseISO } from 'date-fns';
  import { utcToZonedTime, format as utcFormat } from 'date-fns-tz';

ariesmcrae

Typescript: How to use Map(k, v) collection to store unique key/value pairs and perform fast key lookup

Insert a unique key/value pair

interface Person {
  name: string;
  age: number;
}

ariesmcrae

When should you use direct S3 to Lambda vs an EventBridge in between S3 and Lambda

S3 ==> Lambda 
    vs 
S3 ==> EventBridge ==> Lambda

TL;DR

ariesmcrae

Creating an Axios instance vs using Axios directly

TL;DR

It's preferable to create an Axios instance in node.js. Why? Because it offers several advantages over using Axios directly. It provides a more flexible, organized, and maintainable way to manage HTTP requests:

1. Custom Configuration

When you create an instance, you can set default configurations like base URL, headers, timeouts, etc., that will be applied to all requests made using that instance. This eliminates the need to specify these settings for each request.

ariesmcrae

Reasons why workflows should be grouped into multiple AWS Logic Apps in order to help improve the development and maintenance lifecycle of workflows.

Reason 1: Business process affinity

Grouping workflows by related business process helps you implement, test and deploy a logic app without impacting other logic apps.

In the example above there are three Logic App Standard apps - Orders, Shipment Notification, Overnight Batches - each one with multiple logic app workflows that are used to fulfil a specific business process.

Organizing the logic apps this way, allows changes in the Orders Logic App Standard app to be implemented, tested, and deployed without having any impact on Shipment Notification or Overnight Batches.