The Difference between JS Expressions and Statements

[@uchennachukwuba]

Only 29 comments? This channel is the most underrated I’ve ever come across. Clear and concise

[@AhmadJubair]

Thanks for the clear-cut explanation, Steve. I've been working with Reactjs for some time but still had a bit of confusion about the differences between these two. Understood now.

[@AlazTetik]

Yet again, great and useful summary!

[@shahinza]

Thank you professor.

[@alisahi8bp10]

After learning fundamentals of JS & ReactJS from John Smilga (Codding Addict). I was looking for someone who can give a deeper dive into the JS concepts.. And Steve fullfilled everything i was looking forward... All i can say is Thankyou for ur service.

[@bapi6060]

Really great explanations!

[@bostongreen1629]

WOW, I guarantee this will decode makes sense of a lot of concepts when working with JS. BRAVO, the way you explain it

[@MutalibGozalov]

Awesome explanation, thanks

[@s1gma9000]

killer video, u saved me time!!

[@traininfobd]

Sir, if assigning a value like a number is an expression but why assigning a ternary operator is a statement? var num=343; //Expression var alive= isAlive?1:0 / statement chatGPT says these are expression , var x = 5; // assignment expression var y = x + 3; // arithmetic expression ?

[@SteveGriffith-Prof3ssorSt3v3]

The ternary part is an expression. Once you add the var alive = it becomes a statement

[@detaaditya6237]

Hi professor, thanks for the explaination! I want to ask about this part: let x = function(){}. You explained that this is an statement. Are you referring to the whole line or only the `function(){}` part? Because `function(){}` seems to work differently when it is standalone vs when assigned to a variable or parameter of another function. When standalone, it seems like it behaves like a statement. But when it is assigned, it returns the function value - which makes it behave like an expression. Is this true? Please correct me if I'm wrong sir. Once again, thanks a lot!

[@SteveGriffith-Prof3ssorSt3v3]

the whole line let x = function () { } is a statement. function ( ) { } is an expression. It is a value that you could put into a variable. If you wrap it in a set of parentheses and put another set after it then it becomes an IIFE Immediately Invoked Function Expression. you could place function ( ) { } inside a console.log( ) without an error. That's a good indication that it is an expression.

[@mehdi-vl5nn]

like many other topics in the world of programming languages, is heavily dependent on the language designers' interpretation of meanings. Your example: const getRectArea = function(width, height) { return width * height; }; is actually a Function expression in JavaScript, where functions are objects themselves. Another example can be found in JavaScript's Promises, which are often equated with Futures in other languages but are actually coroutines. A funny example from the world of Python is that Tasks are actually Futures.

[@SteveGriffith-Prof3ssorSt3v3]

Dart is a good example. They have Futures instead of Promises.

[@Truth_Taken]

great and simple explanation.

[@MarstonH]

🔥

[@apex-lazer]

Thank you again!

[@Denis_Victorious]

Actually thanks for your awesome content, but I got a bit confused at this one. Why has been stuff like "let f = function(){}" called a Function Expression (according to MDN docs for example), whereas turns out it's a statement (according to the video)🤔

[@SteveGriffith-Prof3ssorSt3v3]

Here you go: function bob( ) { //this is a function declaration which includes a name and starts with the keyword function //gets hoisted with its identifier `bob` } const bob = function ( ) { //this is a function expression //which is part of a statement //`bob` gets hoisted but not the function } ( function ( ) { //this is an IIFE //immediately invoked function expression //not hoisted //but run as soon as it is encountered })( )

[@Denis_Victorious]

@@SteveGriffith-Prof3ssorSt3v3 I've got it eventually, thanks! Turns out I had false assumption about hoisting. I didn't realize let/const get hoisted too, only they don't get initialized in advance (in comparison with var/funcDeclarations) P.S.: I've just noticed your reply (due to my off comments notifications)

[@zidan3948]

Is it safe to say that whatever starts with a keyword is a statement?

[@SteveGriffith-Prof3ssorSt3v3]

Almost. Some keywords are values. Eg true false null this.

[@zidan3948]

@@SteveGriffith-Prof3ssorSt3v3 I think I get it now, thanks a lot!!

[@Sonu_Kr95]

Thanks

[@Stoney_Eagle]

So basically all I have to think of is "Can I fit this in a jsx return", basically I now never have to think about it again. neat☺

[@barungh]

When I come to KZbin, first thing I search for is your new video 🙂

[@Strasbourgeois]

let f = function(){} is a statement that doesn't start with the keyword function but has a function definition within it. So it is a function expression. Am I right? Love your videos very much

[@SteveGriffith-Prof3ssorSt3v3]

Yes. That is correct

[@KurkoVarangian-kg2zj]

This channel has hands down the best explanations

[@chhavimanichoubey9437]

Interview question no doubt

[@SteveGriffith-Prof3ssorSt3v3]

And valuable info for solving a common problem in React.

[@igorr4682]

and you can have an expression inside the statement as well. In summary, expressions produce values, while statements perform actions or control the flow of a code

[@SteveGriffith-Prof3ssorSt3v3]

Yes. A statement can contain an expression but not the other way around.

[@ВолодимирДжичко]

Thanks ❤