JavaScript Problem: Comparing Two Arrays without Loops

We are going to tackle another JavaScript problem in this tutorial. The specific problem is how one can compare two arrays without using any loops.
Would you like to help keep this channel going?
www.patreon.co...
Earn SCRIPT: app.tryroll.co...
Unlimited access to EVERY course for one low price: allthingsjavas...
Access to EVERY course via subscription (get 2 months free): www.skillshare...
Courses offered on Udemy at a discount (access from my site): allthingsjavasc...
Tutorials referred to in this video:
JavaScript Problem Playlist: • JavaScript Problems
ES5 Methods Map and Reduce: • Getting Comfortable wi...
Need Help? pensight.com/x...
For more resources on JavaScript:
www.allthingsja...
#javascript #AllThingsJavaScriptLLC

[@amatiasq]

"Comparing Two Arrays without Loops", then proceeds to nest a `.reduce()` inside a `.map()`...

[@seb.z.g]

😂

[@AllThingsJavaScript]

So grateful for all of you tuning in each week and for your feedback and encouragement. Glad you are all trying to improve your JavaScript skills! #GiveThanks

[@tirmey]

Mapping over an array is kind of intrinsically lopping over it, no? nice solution, anyway!

[@trusabaka9747]

My thoughts exactly.

[@AllThingsJavaScript]

Yes, all those methods iterate over an array.

[@AllThingsJavaScript]

The reason to gravitate toward these methods is that the looping is abstracted away and our code is more declarative, which is easier to reason about.

[@user-zb5jp4ti1d]

Thanks Steve for going to such great lengths to answer the query... you are a legend sir :)

[@AllThingsJavaScript]

My pleasure!

[@magnusfohlstrom]

Without reduce... function compareArray( searchArray, targetArray ) { return searchArray.map(curr => ({[curr]: targetArray.filter(check => curr === check).length})); }

[@AllThingsJavaScript]

Love this one too!

[@MuhammadAdnan2.0]

Have to practice this two time arrays comparing.... 😃

[@lidwinguillermogascagarcia439]

I just started learning js, and to acomplish my project, I need to compare two arrays of food recipes, one is the recipe, and the other array is the ingredients the user have, all I need to do is to check if the users ingredients array contains the ingredients from the recipe array, if true, show a picture of the recipe (trying to make an app that will show me what dishes I could cook with my ingredients).

[@AllThingsJavaScript]

Great task to be working on as you are learning. Best way to learn!

[@magnusfohlstrom]

returns from one line... function compareArray( searchArray, targetArray ) { return searchArray.reduce((obj,curr) => [...obj, {[curr]: targetArray.filter(check => curr === check).length}], []); }

[@AllThingsJavaScript]

Nice approach! I love it!

[@Charlie_904]

i was under the impression that those higher order functions map, filter, reduce etc.. all had built in loops to them.

[@AllThingsJavaScript]

Yes, they all iterate over values. When I say without loops I mean structures that are called loops: for, while etc.

[@Charlie_904]

@@AllThingsJavaScript ahh, gotcha. no problem, love the stuff

[@zhasan66]

Very helpful video tutorial.

[@cpu1001]

Awesome video, thanks for sharing!

[@sajeersayed2008]

Perfect

[@ScottL888]

Nice tutorial, thanks. IMO, it would be more helpful and relevant if you were to use arrow functions.

[@AllThingsJavaScript]

Courses discounts available on my site: allthingsjavascript.com/courses.htm JavaScript Problem Playlist: kzbin.info/aero/PLTo9PCskHpbGawvd3GNAR7mfeFoM61v3y

[@hamidrezaakbarnezhad2018]

so pretty really. I like that. Please solve problems that contains array of objects and operate on each them... and compare solutions in performance and that what is best solution. Tnks

[@AllThingsJavaScript]

What kind of processing are you thinking for each object?

[@hamidrezaakbarnezhad2018]

@@AllThingsJavaScript Operate on heavy arrays of object... For example all sort algorithm on them... Boble sort and ... To sort this array of object. Or for example sort this array of object base on 3 fields like name(asc), age(desc) and score... I want to improve myselt in work with arrays and objects in js. Tnks

[@Well_This_Guy_Says]

Wouldn't JSON.parse(JSON.stringify) work for this? I use it for comparing an array of objects

[@AllThingsJavaScript]

If you were just comparing if they were equal to one another, yes you could use that.

[@TheSwagStatus]

wordList.filter( conditional checking for === with word in wordCheck).length

[@AllThingsJavaScript]

Great way to get the count!

[@hammadrana364]

map also a loopp

[@AllThingsJavaScript]

I get what you are saying, but technically a loop is a control structure. You may not visit every element depending on how you set up the control structure. Map will iterate over every element. This difference is why it is normally not considered a loop.

[@MiroslavPopov]

Hahahah. No loop but map and reduce :)))). Dislike.

[@magnusfohlstrom]

.map .filter .reduce internally they use loop technically. function compareArray( searchArray, targetArray ) { let objArray = [], searchArrayLen = searchArray.length, targetArrayLen = targetArray.length, tot = 0, count = (search, controller = 0) => { tot = targetArray[controller] === search ? tot + 1 : tot; ++controller !== targetArrayLen && count(search, controller); }; (function fill(controller = 0) { tot = 0; count(searchArray[controller]); objArray[controller] = {[searchArray[controller]]: tot}; ++controller !== searchArrayLen && fill(controller); })(); return objArray; };