Record playlist JS1 Week 3

[Dedekind561]

Contents

How to create arrays ( 4/5 mins ) - video 1

• Start with 10 different variables of the same type and then explain why this is a problem. What will happen when we create more and more of these variables?
• Emphasise zero-indexing in arrays
• Modifying arrays ( updating an item at a particular index )

for..of loop ( 5/10 mins ) - video 2

• You can check out the traditional for loop in the previous section
• Demonstrate use of for..of loop with an array

Walk through some code ( 10 mins) - video 3

• Step through a code example like a computer
• Show the debugger
• Pick an example of one function calling another ( days of the week from JS1 Week 3 syllabus notes )

Actions

• @alicagatay add some examples to the repo for your sections

[gregdyke]

Hi

Can I suggest that for of be used as the main way of iterating through arrays? (and regular for be put in a "alternative ways of doing things" video). Tradeoff:

• less practice with accessing through arr[i] (but that's not a frequent occurrence anyway?)
• less confusion because of unnecessarily-complex-for-beginners for loop
• for loop for iterating over an array is unidiomatic in most programming languages

[gregdyke]

Great job on the recordings, Ali, Biruk and Mitch!

For posterity's sake, here are some thoughts (apologies for more pointing out things that could be improved than things that are great):

• The length + discussion format is great!!!! Finally a short set of videos :)
• I wish you'd used the REPL! (trainees don't use the REPL enough, we need to demo it, especially for evaluating expressions)
• I like the 0-indexing explanation
• I'm not super sure about the const explanation (the variable itself didn't actually change, so we can't reassign the array, only its members)
• I like the motivation for arrays. Might have been nice to show a bigger motivating example

let item1 = "milk";
let item2 = "cheese";
let item3 = "eggs";
console.log(item1);
console.log(item2);
console.log(item3);

• Why are we looking at indexOf (and even worse, lastIndexOf)? I'm struggling to come up with a practice example that makes use of it (maybe combining with removeAt, but we would probably use filter for that anyway). Maybe for a pair of arrays instead of a map? Or to find where an element is after a sort?
• Property vs function would be nice to explain clearer (like ok, we don't use brackets, but "because it's a property" is not an explanation that makes sense at this stage)
• shoppingLists are not made up of elements (I'm not sure what they are made up of? items, shoppingListItems, products?)
• maybe consider starting with a while loop? (or at least when explaining the for loop, show the equivalence with while?)
• we need .push() to solve all the exercises (I guess arr[arr.length] is a "tradition", but we didn't teach that either)
• (don't call c-style for loop "traditional" -> "traditional" is often valued as "better")

[gregdyke]

I'm reminded that motivating .push / putting things in new arrays can be quite tricky unless you have a method that does something "cool"/useful with an array - this was solved in fundamentals with "sum" and "pick an element at random". Here it can be solved with the tests that say "return an array" + maybe with console.log being nice at summing an array. It might be a good motivation for introducing .join in the near future