list of programming languages
A relational database stores data in separate tables to avoid redundancy. Customers live in one table, orders in another, products in a third. Each table holds only the data relevant to its entity, and relationships between entities are represented by shared keys: an order row contains a customer_id that points to a customer row. A…
A template literal type is a type built from a string template — the same backtick syntax as JavaScript, but at the type level. It lets you describe strings that match a pattern: \get${string}`, `${number}px`, `${Uppercase}Id`. Combined with unions and infer`, template literal types can split strings, generate combinations, rename keys, and validate formats. They’re…
These two media features let you adapt styles based on how the app is displayed and the visual capabilities of the screen — from standalone PWA mode to HDR displays. Overview of Features Feature Description Values display-mode How the document is displayed browser, standalone, minimal-ui, fullscreen, picture-in-picture dynamic-range Brightness, contrast, and color depth standard, high…
An exception is a signal that something went wrong. It interrupts the normal flow of the program, unwinds the stack, and transfers control to the nearest handler. Dart’s exception system has four keywords: try, catch, on, and finally. The try block contains the code that might throw. The catch block handles the exception. The on…
Method overriding is when a subclass provides its own implementation of a method that already exists in its parent class. The subclass’s method “takes over” — when called on an instance of the subclass, the new method runs instead of the parent’s. A Quick Look at the Example a. What is Method Overriding? Method overriding…
An error handler is not the place to fix the error. It is the place to translate the error into a response. The route throws, the error propagates, and the centralized handler receives it. The handler decides the status code, the message, and the format. It logs the error for the operators, and it sends…
A function that calls a fallible function must decide what to do with the error. It can handle the error, or it can pass it to its own caller. Handling the error is the match or the unwrap. Passing it is propagation. The ? operator is the shorthand for propagation: it extracts the success value…
The INNER JOIN is the most common join type and the one you reach for by default when you need to combine data from two tables. It returns only the rows where the join condition matches in both tables. Rows with no match in either table are excluded from the result. This behavior is what…
TypeScript ships a set of utility types — pre-built type transformations that solve common problems. The five in this chapter are the ones you’ll use daily: Partial<T> makes every property optional, Required<T> makes them required, Readonly<T> makes them read-only, Pick<T, K> selects a subset of properties, and Omit<T, K> removes a subset. Each is a…
These two media features let you adapt styles for accessibility (high-contrast mode) and legacy devices (grid-based screens). Overview of Features Feature Description Values forced-colors Detects forced colors mode (e.g., Windows High Contrast) none, active grid Detects if the device uses a grid-based screen 0, 1 1. forced-colors The forced-colors media feature detects when the user…