JS Type Casting, Converting, and Coercion

[@LR-bc8js]

My favorite teacher on KZbin!!

[@aakashsingh604]

I have learned a lot by coming to your channel. Thanks a lot for it!

[@chesterxp508]

Another very cool tutorial!

[@serhii113]

Thanks! A couple of nuances ;) +{} // NaN +[1] // 1 +[1,2] // NaN "If an object has no primitive value, valueOf returns the object itself." (c) MDN

[@SteveGriffith-Prof3ssorSt3v3]

I've updated my code Gist to reflect the two Array differences for +[1] and +[1,2]. The Arrays get turned into the Primitive string values "1" and "1,2" before being converted to Numbers which is why we get the 1 and NaN results. Not sure why I had 0 written for the Objects. They will always be NaN. Thanks for pointing it out.

[@rmnkot]

Very important core knowledge! Thanks, as always!

[@SteveGriffith-Prof3ssorSt3v3]

My pleasure!

[@Robert-cw9ev]

Thanks for video! I've also looked at other explanations on internet and I found out that: - "" to number is 0; - [] to number is 0, because it first converts to string which is "", then it converts "" to number which is 0; - "" == 0 its true. So equals operator converts both to number, which means that "" to number is 0.

[@BrendanMetcalfe]

Looks like you put in a lot of work on this! Good work man

[@katherineprokofieva5707]

thanks for your video!

[@joaovaz3473]

Great video, always! A question: isn't an empty array a falsy value?

[@SteveGriffith-Prof3ssorSt3v3]

Nope. Everything that is not falsy is truthy in JS. The falsy values are: false, 0, "", null, undefined, and NaN. Arrays are Objects. They are not on the list, so they are truthy. Run this: if( [ ] ){ console.log('array is truthy'); } However, think about this - Convert an empty Array to a String and you get "". Convert that into a Boolean and you get false.

[@joaovaz3473]

@@SteveGriffith-Prof3ssorSt3v3 Ahh, ok. Thanks!

[@tracyadams6787]

Great video. Any chance you could post the link to the operator precedence reference?

[@SteveGriffith-Prof3ssorSt3v3]

It is in the code gist linked to in the description

[@webb-developer]

☑

[@siddharthapothan5165]

Your videos are really helpfull, learnt a lot. But is Number({}) value 0? Thanks!!!

[@SteveGriffith-Prof3ssorSt3v3]

That was a copy paste error in my comments. The gist was updated to show that converting an empty object to a number gives you NaN.

[@guignolguignol5340]

is there in ASP classic or javascript function like CURL in PHP

[@SteveGriffith-Prof3ssorSt3v3]

fetch( ) is the modern JavaScript method for making HTTP Requests. XMLHttpRequest is the old JS method for making HTTP Requests.

[@guignolguignol5340]

@@SteveGriffith-Prof3ssorSt3v3 Thank you, Mr. Steve, in your view, what you will use to do better

[@jassihambran]

hey steve. Could you help us in how to setup terminal to run javascript files without any extension?Thanks in advance

[@aarong9327]

Type node in your terminal and it'll run the code in that file.

[@jassihambran]

@@aarong9327 it does not. When i try it says file could not be found.

[@SteveGriffith-Prof3ssorSt3v3]

It does on Linux and MacOS. I haven't tried on Windows.

[@NairiKhachatryan]

let emptyStr = '' Number(emptyStr) // 0