list of programming languages
A table without an index is a book without a table of contents. Every query that needs to find a specific row must read the entire table from the first row to the last. For a table with a thousand rows, that is unnoticeable. For a table with a hundred million rows, that is a…
The tsconfig.json is not a configuration file. It is a program. Every flag in the compilerOptions object changes what the compiler accepts, what it rejects, what it emits, and how it resolves the modules. The previous chapter covered the strict flags, which are the safety’s core. This chapter covers the rest: the module system, the…
A Dart command-line interface is a program that reads arguments from main(List<String> args), parses them into structured values, and routes execution to the correct logic. The package:args library provides two levels of abstraction for this: ArgParser for parsing flags and options in a single-command script, and CommandRunner for building multi-command CLIs with subcommands, automatic help…
This chapter is a condensed reference for the JavaScript language and its runtime environment. It is organized for lookup, not for reading. Each table covers one topic, and each entry is a fact that has a precise answer. The entries are drawn from the ECMAScript specification, the MDN documentation, and the behaviors that are verified…
Supertest is a library that lets you make HTTP requests against your Express application and assert on the response, without starting a server on a fixed port and without writing manual socket code. It extends SuperAgent, an HTTP client, and adds a chainable .expect() method that validates status codes, headers, and body content in a…
Lifetimes are Rust’s mechanism for tracking how long references remain valid. The basic rules—every reference has a lifetime, the compiler infers them where possible, and explicit annotations are needed when the relationship between input and output lifetimes is ambiguous—are covered in any introduction to the language. The advanced material is about what happens when lifetimes…
An index is only as good as the data structure underneath it. The previous chapter established why indexes exist and how selectivity drives the optimizer’s decisions. This chapter goes one level deeper and examines the three fundamental index structures that relational databases actually implement: the B-tree, the hash table, and the bitmap. Each structure makes…
A TypeScript project starts as a single tsconfig.json and a single src directory. It grows into a monorepo with a shared library, several applications, and the test projects, and the single project’s compilation becomes the bottleneck. Every build recompiles everything, the editor’s IntelliSense slows down, and the changes to one package trigger the rebuilds of…
package:shelf is the Dart team’s official HTTP server library. It is deliberately minimal. Where a framework like Express or Dart Frog provides routing, middleware, and project structure out of the box, Shelf provides a single abstraction—the Handler—and a Pipeline for composing middleware around it . Everything else is assembled from smaller packages: shelf_router for route…
Mocking an external API by stubbing fetch or axios is a trap. The stub intercepts the function call, not the network request. The application’s HTTP client—with its interceptors, retry logic, serialization, and status-code handling—never runs. The test passes, but it is testing a code path that does not exist in production. Mock Service Worker (MSW)…