Answers

Block scope, the temporal dead zone, and why var still causes surprises.

Declarations versus expressions, default and rest parameters, and functions as values.

Concise function syntax, implicit returns, and how arrow functions change what this means.

Property access, computed keys, nested data, and reading values that might not be there.

Indexes, length, searching, slicing, and the array of objects behind every list.

Pulling values out of objects and arrays, and copying them without mutation.

The transformations you will reach for in every list you render.

Named and default exports, and how a component file is wired together.

Asynchronous work, error handling, and the model behind data fetching.

Write a component, put values into JSX with braces, and render the first card of the watchlist.

Hand a component its data as props, and draw three different shows with one card component.

Turn an array of shows into cards with map, and give React a key it can trust.

Hide the shows you would not watch, and put a badge on the ones you would.

Give each component its own file, and wire the app back together with export and import.

Attach a click handler to a show card, and pass the function instead of calling it.

Pass an onPlay handler from App through ShowCard into a Button.

See why a click on Play also hits the card, and how to stop a link leaving the page.

Give a show card memory with useState, so Watched stays after the click.

Watch React re-run the card, compare the result, and apply only the difference.

See that a handler still reads the watched flag from the click, even after you set it.

Queue several watched-count updates, and use an updater when the next value depends on the last.

Copy a show object with spread when you change a field, including a nested rating.

Toggle watched on a list of shows by mapping to a new array, not by mutating.

Give the watchlist a heading, a ShowList, and a count that follows the cards.

Keep the search field in state, and submit it without reloading the preview.

Fetch matching shows when Search is pressed, and show loading, error, or cards.

Keep search results and the watchlist as two arrays, and copy a show into the list.

Skip a show that is already saved, and take one off the list without mutating.

Select a saved show in state, and load extra fields from TVMaze when you ask.