Learn Algolia, Lodash and Svelte

JavaScript community has been shaken recently by a release of Svelte 3 and for a good reason - it's a completely different approach than React or Vue. To quote the docs:

"[Svelte](https://svelte.dev/) is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue do the bulk of their work in the browser, Svelte shifts that work into a compile step that happens when you build your app."

**The best part?** If you have 26 spare minutes you can learn the basics of Svelte 3 and start building your own apps with it!

Enjoy!



The magical disappearing UI framework

 - The web's JavaScript bloat crisis, solved. Svelte turns your templates into tiny, framework-less vanilla JavaScript.
 - Simple and familiar. Build apps out of composable, easy-to-write blocks using languages you already know.
 - Super fast, rock solid. Compile-time static analysis ensures the browser does no more work than it needs to.

svelte

Up and running with Svelte 3

Today’s users expect great things from their search experiences — speed, relevance, and usability, to name a few. Algolia provides developers with out-of-the-box and customizable search experiences that are a joy to build.

This introductory course on the Algolia search solution focuses on the user-facing part of search. Using the Algolia InstantSearch.js front-end library, we’ll see how to build an engaging search experience in no time. (28 minutes, to be exact.) 

**Prerequisites:** 
You don’t need previous experience with search to follow this course — we’ll use an example index with an e-commerce data set preconfigured. We will work mainly in JavaScript, so basic JS knowledge is expected.

If you want to play with your own index settings and data set, you can [create a free Algolia account here](https://www.algolia.com/users/sign_up/hacker/?utm_medium=link&utm_source=egghead&utm_campaign=education), but this is not required to follow along with this first course. 

Algolia's full suite APIs enable teams to develop unique search and discovery experiences for their customers across all platforms and devices. Type a query. Click a link. Open an app. Everything your customers do sends a signal about what they want. Algolia decodes that intent to deliver the right content - instantly.

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Getting Started with Algolia InstantSearch.js

[Lodash](https://lodash.com/docs/) is a collection of utilities that have become a staple of modern web development. This collection will show you how to re-create its most common methods using simple JavaScript techniques available in any modern web browser. In addition to re-building tools like `_.merge`, `_.get` and `_.debounce` from scratch you will also learn how to replace them completely in some cases with modern syntax such as [optional chaining](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining), [nullish coalescing](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator) and [Object.fromEntries](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/fromEntries).

This collection should interest the following groups:
- Those who want to better understand common JavaScript patterns
- Engineers who want to reduce their dependence on Lodash (for performance or other reasons)
- Candidates preparing for a technical job interview (where it is common to be asked how to implement some of these methods).

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

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Recreating Popular JavaScript Utility Methods from Lodash

A modern JavaScript utility library delivering modularity, performance & extras.

lodash

This lesson shows how to refactor your old loops into using a simpler and more powerful lodash-style. We will start by looking at how many people traditionally write JavaScript `for` loops and then talk about the alternate style and benefits that Lodash offers.

Lodash: Refactoring Simple For Loops

AngularJS is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications. Its goal is to augment web-based applications with model–view–controller (MVC) capability, in an effort to make both development and testing easier.

angularjs

Lodash has an enormous amount of utility functions for dealing with collections and objects in javascript. You can use it in your AngularJS applications to "debounce" user input, or add delay between user actions. This is a common technique for text input to hold firing service calls until the user stops typing for a fraction of a second.

Debounce (delay) User Input in AngularJS with Lodash

Imagine if looking at your business logic read as simple as a story from a children's book. That's exactly what we'll cover by learning how to compose small pieces of business logic and also set them up for further composition in the future.

We're showing a list of fictional tweets in a trivial React component created with create-react-app, however the example is not React specific and can be applied to any framework/environment.

Our example will refactor out business logic from a non-composable function to small composable pieces. To accomplish this we'll be using flow, filter and map from lodash/fp, which is included in the regular lodash npm package.

This approach works well in any environment where you're not relying on object references to your original data, as our functional approach creates new collection objects instead of mutating them.

Guide to lodash/fp: https://github.com/lodash/lodash/wiki/FP-Guide


Refactor Business Logic to Composable Functions with Lodash

Lodash's "sortBy" method helps you sort data in your collections and "sortedIndex" helps you find where to place new data. In this video, John walks you through how to use each of these methods and how they can work together.

Lodash - sortBy and sortedIndex

Property access in Javascript can be problematic - especially when dealing with nested Objects and Arrays. Doing it manually and in a safe manner requires tons of boilerplate inside conditionals and results in a defensive style of coding. In this lesson we look at why this is a problem & how to overcome it using the `get` method from the popular utility library `Lodash`

Safer property access with Lodash's 'get' method

Logic often gets added to our loops. We need to iterate over a collection, and get the sum of values, for instance. This approach can lead to complicated methods, that are hard to test. Using Lodash (Underscore), we are going to extract logic in a large loop body into well named methods. The result will be cleaner and easier to understand.

Refactoring: Replace Loop with Collection Closure using Lodash

Learn how to use Object.assign to combine multiple objects together. This pattern is helpful when writing libraries that have a set of default options where you want to allow a user to override specific options. You'll also learn how to use a third party library to recursively merge nested objects together.

Combine Objects with Object.assign and Lodash merge

Lodash is a toolkit of Javascript functions that provides clean, performant methods for manipulating objects and collections. It is a "fork" of the Underscore library and provides additional functionality as well as some serious performance improvements. If you aren't using Lodash, you should be.

Introduction to Lodash

This will get you started on how to setup the Javascript API client of Algolia search solution. To follow along the video having a free Algolia account already setup will make things easier (but is not required). Once the client is setup we will test it by pushing a couple of records to an index.  

Set up the Algolia JavaScript Client

We’ll load a simple JSON file containing 500 actors records from disk and push it to our Algolia index using the Javascript API client.

Push JSON Data to an Algolia Index from the JavaScript Client

We’ll learn how to push a small amount of data from a local MySQL database to an Algolia index. The first step is to connect to the DB using the `mysql` package, then select all records from the DB and finally push them to Algolia using the JS API client.

Push MySQL Data to an Algolia Index from the JS Client

Using the Lodash library, we’ll see how to split large amounts of data from a local MySQL database into smaller chunks and push them to an Algolia index.  

Push Chunks of Large MySQL Data to an Algolia Index with Lodash

Before playing with Instantsearch widgets and build a rich search experience, the fundamental step is to understand what the library will be dealing with. In this lesson we we’ll cover the anatomy of the JSON search API response send back by Algolia for each search query and how it can be used.

Anatomy of an Algolia Search API Response

We now have a good understanding of the API Response structure, we could go playing with instantsearch JS library right away, that said this Library is building on top of the JS API Client. To get a better grasp on how it works at a lower level, let’s play first with raw hits straight from the JS API client, we’ll take care of better UI with Instantsearch JS right after that.

Leverage the Algolia JS API Client to Display Raw Hits from the API Response

The first step to implement Algolia on the front end using Instantsearch : importing and setting up the library with your credentials. This is what will allow the library to initiate the connection to Algolia servers and the first step to complete before adding some useful widgets.

Set up the Instantsearch JS Library

In this lesson we’ll build a search experience reduced to it’s 2 essential components : a search input and the displayed results. As simple as it is, to build this from scratch would require a fair amount of work. Between listening to the input, making the api call, parsing and displaying the result... To build this using Algolia’s Instantsearch library requires a few lines of code with simply two widgets: the Searchbox and the Hits widget.

Search an Algolia Index with Instantsearch JS searchbox and hits widgets

Displaying barebones Hits won’t catch your user’s attention. The UI is key to provide a good search experience and hits are the meat of this experience so they need extra attention. By using Mustache templating we’ll see how to display rich results to your users. 

Display Rich results with templates in the Hits widget for Instantsearch JS

Every  good search UX make users understand instantly why a given hit is being displayed as part of the result set. One way to achieve that is to highlight the keywords from the query directly inside the Hits. This is built in the API JSON response and in this video we’ll explain how to leverage it easily.