85 docs tagged with "junior"

Big O, Omega and Theta, complexity classes, abstract data types, arrays, linked lists, stacks, queues, hash tables, trees, heaps, graphs, sorting, search and common algorithmic techniques

API Routes in pages/api, submitting a form to an API Route, validation and errors

File conventions of the app/ directory, segments, route groups, parallel and intercepting routes

Array methods by group, mutating and non-mutating, common pitfalls

Primitives, any, unknown, never, void, arrays, tuples, unions and literals

Naming, DRY / KISS / YAGNI and when DRY hurts, Clean Code principles, code smells

bind(), call(), apply()

Content, padding, border and margin, box-sizing, margin collapsing, block vs inline, block formatting context, overflow, logical properties

Cookies vs localStorage vs sessionStorage, cookie attributes and security

Legacy class components, lifecycle methods and their hook equivalents

Class syntax, inheritance, private fields and static methods

A function that remembers the variables of the scope it was created in

An index of live-coding tasks - bind, call/apply, Promise.all, debounce, deep copy, memoize, flat, event emitter, LRU cache - and where each is solved

reset vs revert vs restore, reset modes, reflog, stash, switch, fetch vs pull, tags

Components, elements and JSX, purity, fragments

View, Text, Image, TextInput, Pressable, ScrollView, Modal and their native views; text only inside Text, network images need a size, expo-image

Same-Origin Policy, what an origin is, preflight and credentials

CSS variables, var() with a fallback, cascade and inheritance, invalid at computed-value time, @property, theming with light-dark() and color-mix(), vs Sass variables

Tracks and fr, repeat() with auto-fill vs auto-fit, line placement and grid areas, implicit grid, subgrid, Grid vs Flexbox

Combinators, attribute selectors, :nth-child vs :nth-of-type, :focus-visible, pseudo-classes vs pseudo-elements, :has(), right-to-left matching

Transitions vs keyframe animations, why to animate transform and opacity, will-change, CSS vs JavaScript animations, reduced motion

What data types exist in modern JS

PostgreSQL data types, integers, numeric vs floating point, text, timestamp vs timestamptz, boolean, uuid, json vs jsonb, identity columns

React Native DevTools and its panels, LogBox, native logs from Xcode and logcat, crash reporting in production with source maps

Console, breakpoints, DevTools panels, React and Redux DevTools

SDLC stages, Waterfall vs Agile, Scrum roles and events, Kanban, Scrum vs Kanban

Capturing and bubbling, target vs currentTarget, delegation, listener options

Numeric, string and const enums, and why unions often replace them

NEXT_PUBLIC_ variables inlined at build time vs server variables read at runtime, .env file order, one Docker image for several environments

throw, try...catch...finally, custom errors and errors in async code

EventEmitter, synchronous listeners, the special error event, once and promises, listener leaks, EventEmitter vs EventTarget

The fs module, promise vs callback vs sync APIs, common operations, paths, existence checks, streams for large files

Main and cross axes, container and item properties, flex-grow / shrink / basis and flex 1, gap and wrapping, the min-width trap, order

How Flexbox in React Native differs from the web, alignment properties and their values

Function Declarations, Function Expressions, and Arrow Functions

Type parameters, constraints, defaults and generic React components

pushState and replaceState, the popstate event, hash vs history routing, and the Navigation API

Built-in hooks at a glance, the Rules of Hooks and custom hooks

From a URL to pixels - DNS, connection, parsing, the rendering pipeline

Semantic markup, script loading, nesting rules, data attributes, viewport, form validation

Methods, status codes, caching, HTTP versions and requests with fetch

Creating an HTTP server with node:http, request and response as streams, reading the body, headers, making requests with fetch

IntersectionObserver, ResizeObserver and MutationObserver, when their callbacks run, lazy loading, infinite scroll and the ResizeObserver loop error

Rendering lists with map, choosing a key, an index as a key, resetting state with a key

Merge vs rebase, fast-forward and merge commits, squash, interactive rebase, cherry-pick and conflicts

Link and prefetching, useRouter, usePathname, useSearchParams, redirect and where to redirect

React Navigation vs Expo Router, stack / tabs / drawer, screens that stay mounted, navigate vs push vs popTo, typed params, auth flow

What Next.js adds to React, App Router vs Pages Router, when not to use it

Cloning objects, accessing properties, iterating, Object static methods

Object shapes, interfaces, optional and readonly properties, index signatures

Encapsulation, inheritance, polymorphism and abstraction with TypeScript examples, composition over inheritance

npm, pnpm, Yarn and Bun, lockfiles, semver ranges, dependency types, workspaces, Corepack, install scripts

pages/ routing, dynamic routes, _app and _document, navigation and redirects

Platform-specific file extensions, Platform.OS, Platform.select and Platform.Version

position values, containing block, why sticky does not stick, stacking context and z-index, top layer, anchor positioning, ways to center an element

Imperative vs declarative programming, with examples in JavaScript

Passing data and callbacks, default values, children, typing and prop drilling

createContext, providers, useContext and use, re-renders of consumers

React Router modes, nested routes, navigation hooks, loaders and protected routes

useRef, DOM refs, callback refs, ref as a prop and useImperativeHandle

Creating regular expressions, flags, methods and basic syntax

One-to-one, one-to-many and many-to-many relationships, how each is built with foreign keys, junction tables, querying with JOIN

SSG, ISR, SSR and CSR in the Pages Router, automatic static optimization

Mobile-first media queries and range syntax, CSS units, clamp() / min() / max(), container queries, srcset and sizes vs picture, user preference queries

useEffect dependencies, cleanup order, StrictMode, race conditions and useLayoutEffect

Cascade order, specificity, :is() / :where() / :has(), nesting, @layer, inheritance and the inherit / initial / unset / revert keywords

DML, DDL, DCL and TCL, SELECT and the logical order of clauses, JOIN types, GROUP BY and HAVING, subqueries and CTEs, upsert and RETURNING

NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY with ON DELETE actions, CHECK and DEFAULT, and how NULL interacts with them

useState and useReducer, state as a snapshot, batching, immutable updates

AsyncStorage, MMKV, SecureStore and SQLite, where each kind of data goes on the device, tokens in Keychain / Keystore, persisting app state

StyleSheet API, how styles differ from CSS, responsive sizes with useWindowDimensions, custom fonts

Event handlers, SyntheticEvent, event delegation on the root and differences from DOM events

Types of tests, pyramid vs trophy, test doubles, coverage, AAA, TDD and BDD, test runners and E2E tools

What the `this` keyword refers to in JavaScript

The as syntax, as const, satisfies, non-null assertion and when a type guard is safer

typeof, instanceof, in, equality, discriminated unions, type predicates and assertion functions

Declaration merging, extends vs intersection, implicit index signatures and which one to choose

Props, children, events, hooks, context, wrapping native elements and ref as a prop in React 19

Parts of a URL, new URL and URLSearchParams, percent-encoding, encodeURI vs encodeURIComponent

Partial, Required, Readonly, Pick, Omit, Record, Exclude, Extract, NonNullable, ReturnType, Parameters, Awaited and NoInfer

var, let and const, hoisting and the temporal dead zone

WCAG and its levels, semantic HTML, accessible names, keyboard and focus, ARIA rules, contrast, testing

What Node.js is, V8 and libuv, the thread pool, non-blocking I/O, when Node fits and when it does not, release lines

What React Native is, how it differs from React for the web, Flutter and native apps, Expo vs bare projects

Controlled and uncontrolled inputs, form Actions in React 19, form libraries