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Software: explore STEM content (page 9 of 25) · openstem

All fields Software Mathematics Physics Chemistry Biology Engineering Astronomy Environmental Other Software Software groups

Explore STEM Content

Search the community's STEM library — free to study, yours to make your own.

Software

Programming, algorithms and systems on openstem — flashcards, notes, quizzes, sketches and flowcharts shared by the community. Study free, or clone anything into your library.

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Note~382 words · 2 min

Designing a REST API REST (Representational State Transfer) models server-side resources as URLs and uses HTTP verbs to express actions on those resources. HTTP verbs and their semantics Idempotency An operation is idempotent if calling it

Software

Software · L4 · Designing a REST API

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Software · L4 · Designing a REST API

Collection2 items

01Rendering Architecture: RSC, Streaming & Caching

02Routing, Middleware & Edge Runtime

Software

Software · L4 · Next.js

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Software · L4 · Next.js

Quiz5 questions

Which utility type would you use to build a PATCH request body where every field of User is optional?

ARequired<User>BPartial<User>CReadonly<User>DPick<User, never>

Software

Software · L2 · TypeScript: Utility Types

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Software · L2 · TypeScript: Utility Types

Collection2 items

01Distributed Systems Deep Dive

02System Design Practice

Software

Software · L4 · System Design

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Software · L4 · System Design

Quiz5 questions

What runs first when a request arrives at a Nest application?

AMiddlewareBGuardsCPipesDThe route handler

Software

Software · L1 · NestJS: Architecture & Routing Check

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Software · L1 · NestJS: Architecture & Routing Check

Flashcards10 cards

Why use semantic HTML elements?1 / 10

Elements like <header>, <nav>, <main>, <article>, <footer> convey meaning to browsers, screen readers, and search engines — improving accessibility and SEO over generic <div> soup. Assistive tech uses them for navigation landmarks.

Software

HTML & Semantics

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HTML & Semantics

Flowchart11 objects

Software

Software · L2 · Dart: Error Handling & Testing · flowchart

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Software · L2 · Dart: Error Handling & Testing · flowchart

Flowchart15 objects

Software

Software · L1 · Python: Choosing the Right Collection · flowchart

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Software · L1 · Python: Choosing the Right Collection · flowchart

Note~122 words · 1 min

Three Kinds of Method Every method in a Python class body is one of three flavors, distinguished by what it's implicitly handed as its first argument — and that first argument tells you exactly what the method is allowed to touch. Deciding

Software

Software · L2 · Python: classmethod, staticmethod, or Instance Method?

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Software · L2 · Python: classmethod, staticmethod, or Instance Method?

Flashcards10 cards

What is a Docker image layer?1 / 10

Each instruction in a Dockerfile creates a read-only layer; layers are stacked and cached, and a container adds a thin writable layer on top.

Software

Container Internals & Images

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Container Internals & Images

Flashcards10 cards

What is a trait in Rust?1 / 10

A trait defines shared behavior as a set of method signatures that types can implement. It is Rust's mechanism for interface-like polymorphism and abstraction over types.

Software

Traits & Generics

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Traits & Generics

Flowchart16 objects

Software

Software · L2 · Testing: CI Test Execution Strategy · flowchart

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Software · L2 · Testing: CI Test Execution Strategy · flowchart

Quiz5 questions

What does a Postgres standby replay to reconstruct the primary's data?

AThe Write-Ahead Log (WAL)BA daily pg_dump backupCThe query planner's cacheDThe client's connection log

Software

Software · L2 · PostgreSQL: Replication & High Availability

@openstem

Software · L2 · PostgreSQL: Replication & High Availability

Flashcards10 cards

What is the difference between an interface and an abstract class?1 / 10

An interface declares method signatures (and default methods since Java 8) with no state; a class can implement many. An abstract class can have state, constructors, and concrete methods, but a class extends only one. Use interfaces for capability, abstract classes for shared base implementation.

Software

OOP & Collections

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OOP & Collections

Flashcards10 cards

What is `Option<T>` and why does Rust have no null?1 / 10

`Option<T>` is an enum with variants `Some(T)` and `None`. Rust has no null pointer — absence of a value is encoded in the type system, forcing you to handle the None case explicitly. This eliminates null-pointer dereferences.

Software

Enums & Error Handling

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Enums & Error Handling

Flowchart27 objects

Software

Software · L4 · Saga Execution With Compensation

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Software · L4 · Saga Execution With Compensation

Flashcards10 cards

What problem do Node streams solve?1 / 10

They process data in chunks as it arrives instead of buffering the whole payload in memory, enabling constant-memory handling of large or unbounded data.

Software

Streams & Buffers

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Streams & Buffers

Flashcards8 cards

What makes a function 'pure'?1 / 8

Its output depends only on its inputs (no reliance on external mutable state), and calling it causes no observable side effects (no I/O, no mutation of arguments or globals).

Software

Functional Programming Concepts

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Functional Programming Concepts

Flashcards10 cards

What is the role of a Nest module?1 / 10

A class annotated with `@Module` that groups related providers, controllers, imports, and exports into a cohesive feature boundary.

Software

Modules & Providers

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Modules & Providers

Quiz5 questions

An object has 8 optional constructor parameters. Which pattern fits best?

ABuilderBSingletonCPrototypeDFactory Method

Software

Software · L1 · Design Patterns: Choosing a Creational Pattern

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Software · L1 · Design Patterns: Choosing a Creational Pattern

Flashcards10 cards

What is the difference between a mock and a stub?1 / 10

A stub returns canned responses to make a test run; a mock additionally records and asserts on how it was called (behavior verification).

Software

Unit Testing & Mocking

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Unit Testing & Mocking

Quiz2 questions

Binary uses only two digits. Which two?

A1 and 2B0 and 1C0 and 9DA and B

Software

Software · L2 · Binary and the Internet

@openstem

Software · L2 · Binary and the Internet

Note~100 words · 1 min

What Happens Before Your Handler Runs Every incoming request passes through several distinct layers, each with a specific job, before reaching the controller method you wrote. An exception filter sits outside this whole flow — it catches an

Software

Software · L1 · NestJS: Request Lifecycle

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Software · L1 · NestJS: Request Lifecycle

Flowchart15 objects

Software

Software · L1 · Rust: Move, Borrow, or Clone? · flowchart

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Software · L1 · Rust: Move, Borrow, or Clone? · flowchart

Note~109 words · 1 min

One Branch per Change Instead of committing directly to main, most teams isolate each change on its own short-lived branch. That keeps main always deployable and gives reviewers a clean diff to look at. If review comes back with requested c

Software

Software · L1 · Git & Dev Workflow: The Feature Branch Workflow

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Software · L1 · Git & Dev Workflow: The Feature Branch Workflow

Flashcards10 cards

What two guarantees does TLS provide for data in transit?1 / 10

Confidentiality (encryption) and integrity (tamper detection), plus server authentication via certificates.

Software

TLS & Network Security

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TLS & Network Security

Flashcards10 cards

What are the three rules of ownership in Rust?1 / 10

1) Each value has a single owner. 2) There can be only one owner at a time. 3) When the owner goes out of scope, the value is dropped (freed). This is how Rust guarantees memory safety without a garbage collector.

Software

Ownership & Borrowing

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Ownership & Borrowing

Flashcards10 cards

What is MongoDB's data model?1 / 10

A document database: data is stored as flexible, JSON-like documents (BSON) grouped into collections. Documents in a collection need not share the same schema. Maps naturally to objects in code — no joins/normalization required for nested data.

Software

Documents & Queries

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Documents & Queries

Quiz5 questions

What does a `useFactory` provider let you do that `useClass` doesn't?

ACompute the provided value at runtime, optionally injecting other providersBSkip dependency injection entirelyCRegister the provider globally by defaultDAvoid needing an injection token

Software

Software · L2 · NestJS: Modules, Providers & Pipes Check

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Software · L2 · NestJS: Modules, Providers & Pipes Check

Flowchart11 objects

Software

Software · L1 · Go: new(), make(), or a Literal? · flowchart

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Software · L1 · Go: new(), make(), or a Literal? · flowchart

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