Tagged: Tutorial
109 articles tagged Tutorial across all clusters on CodeWalkers.
List and Dict Comprehensions in Python
A comprehension builds a list or a dictionary from an existing iterable in one expression. The syntax for both forms, filtering, conditional values, nesting, and the cases where a plain loop is the better answer.
unknown, any, and Runtime Data in TypeScript
Why unknown beats any at the boundaries of a TypeScript app, how to validate runtime data such as parsed JSON, and what type assertions actually cost.
Union Types and Narrowing in TypeScript
Union types, literal types, and the narrowing toolkit: typeof, in, instanceof, discriminated unions, and exhaustiveness checking with never.
PHP Tutorials: Build Real Projects Step by Step
Hands-on PHP tutorials from the classic CodeWalkers archive, rebuilt for modern PHP: dynamic sites, a mini chat app, search, email, image handling, and more.
Interfaces and Type Aliases in TypeScript
Interfaces and type aliases both name shapes in TypeScript. Learn the real differences: extension, declaration merging, what each form can express, and which to default to.
The First Types to Learn in TypeScript
Primitive annotations, arrays, object types, and type inference in TypeScript: what to annotate, what to let the compiler infer, and why const and let behave differently.
TypeScript Types
The TypeScript type system from the ground up: the first annotations, interfaces and type aliases, union types and narrowing, and handling unknown runtime data.
API Contracts and Shared Models in TypeScript
Modelling a request and response once, why a shared type is not validation, generating types from an OpenAPI or GraphQL schema, and changing a contract without breaking callers.
TypeScript with React: Props, Children, State, and Events
JSX settings, component prop types, children and native element props, typed state and refs, event handlers, and what types cannot enforce across the server and client boundary.
Timers, Ordering, and Race Conditions in JavaScript
setTimeout and setInterval, the order callbacks actually print in, the stale response race that breaks search boxes, debounce and throttle, and cleaning up when the owner disappears.
Files, Environment Variables, and Small Automations
Reading and writing files with fs/promises, paths that survive the wrong working folder, keeping keys out of code with env files, and one worked bulk edit with a dry run.
TypeScript Tooling and Project Workflow
The compiler commands worth knowing, why transpiling is not type checking, what the editor language service does, wiring a real check into CI, and migrating a JavaScript codebase.
Swift allSatisfy: Check That Every Element Passes a Test
The allSatisfy(_:) method answers one question about a whole collection: does every element pass this test? Syntax, the empty-collection result that surprises people, and when filter is the method you actually wanted.
Modules, Imports, and Exports in JavaScript
Splitting JavaScript across files: named against default exports, import paths that actually resolve, ES modules against CommonJS, script type module, and load-order surprises.
tsconfig.json Explained
What tsconfig.json controls, which files actually get checked, what strict mode turns on, the flags that stay off until you name them, and how to share a config across a workspace.
package.json, npm, and Scripts
The fields Node and npm each read, why dependencies and devDependencies are separate lists, naming commands as npm scripts, what a lockfile protects, and when npx is the right tool.
Listener Cleanup and Page Lifecycle
removeEventListener and why it so often does nothing, retiring listeners with one AbortController, script defer against DOMContentLoaded, and why these leaks survive a framework.
TypeScript Tooling
The half of TypeScript that is not types: tsconfig.json, the split between transpiling and type checking, React components, and API contracts between a frontend and its server.
TypeScript Utility Types: Pick, Omit, Partial, and Record
Pick, Omit, Partial, Required, Record, Readonly, ReturnType, and Awaited: what each one really does, where the checking is looser than it looks, and when to name the result.
Python Dictionaries: Keys, Values, Updates, Loops, and JSON
A Python dictionary stores values under names you choose instead of numbered positions. Creating one, reading keys safely, updating and merging, looping over views, counting and grouping, and the JSON boundary.
Events, Forms, and User Input in JavaScript
addEventListener and the event object, preventDefault, one delegated listener for a whole list, reading a form with FormData, the browser's own validation, and honest loading states.
Generic Functions and Types in TypeScript
Type parameters explained without the theory: what a generic buys you, how inference fills it in at the call site, constraints with extends, generic types, and defaults.
Running JavaScript with Node
Checking your install and reading version numbers, running a file, what type module changes, reading arguments from process.argv, the two output streams, and exit codes.
Typing Functions and Callbacks in TypeScript
Parameter and return annotations, optional and rest parameters, named function types, and the contextual typing that removes most callback annotations.
Fetch, JSON, and the Network in JavaScript
Requesting data with fetch, the response.ok check most tutorials skip, parsing JSON, sending data with POST, telling a bad answer from no usable answer, and timeouts with AbortController.
TypeScript Generics and Function Types
Reusable types in TypeScript: function and callback types, type parameters with constraints and defaults, and the built-in utility types that derive one shape from another.
Objects, Arrays, and Destructuring in JavaScript
Object literals and property access, the array methods worth knowing, destructuring, spread and rest, when Map and Set beat a plain object, and copying without mutating.
Swift Sets: Unique Values, Set Algebra, and Membership Tests
A Swift Set stores unique values with no order and answers membership questions in constant time on average. How to create one, run set algebra, make your own types storable, and decide between Set and Array.
Python Lists: Create, Slice, and Iterate
A Python list keeps items in the order you put them and lets you change that order later. How to create one, index and slice it, add and remove items, copy it safely, and recognise the jobs a list is wrong for.
Selecting Elements and Updating the Page
querySelector and querySelectorAll, textContent against innerHTML and when each is safe, adding and removing classes, attributes and data values, and building or deleting elements.
Promises and async/await in JavaScript
What a promise is and the three states it can be in, then and catch, the async and await keywords, waiting on overlapping work with Promise.all, and where a thrown error ends up.
JavaScript with Node
JavaScript run on your own machine: what Node is, the handful of terminal commands you actually need, and the three guides covering running files, package.json, and file automations.
Functions, Callbacks, and Closures in JavaScript
Declarations against expressions, arrow functions and what this binds to, default and rest parameters, callbacks, closures, and functions that take or return functions.
JavaScript and the DOM
The JavaScript that changes a web page: finding and updating elements, reacting to clicks and forms, and taking your listeners back off again.
Understanding typealias in Swift
The typealias keyword gives an existing type a second name. What it does to closures, tuples, dictionaries, and generics, what it deliberately does not do, and the errors it produces.
JavaScript Async
The JavaScript that runs later: promises and await, fetching data over the network, and the ordering rules behind timers and race conditions.
Values, Variables, and Equality in JavaScript
let and const, the primitive types, type coercion, == against ===, truthiness, the difference between null and undefined, and the ?? and ?. operators.
JavaScript Language Basics
The four pieces of JavaScript every other page assumes: values and equality, functions and closures, objects and arrays, and modules that split code across files.
HTML Tables: Rows, Cells, Headers, and Accessible Markup
Build real HTML tables for tabular data: the table, tr, and td grid model, headers and captions, spanning cells, and accessible markup.
HTML Elements and Structure
The core HTML elements that give a page its shape: the document skeleton, headings and text, lists, links, and images, with small valid examples.
CSS Grid: Two-Dimensional Layout
How CSS grid lays out two dimensions: grid-template-columns, rows, gaps between tracks, and placing items across the grid.
CSS Custom Properties: Variables, Fallbacks, and Themes
Define reusable CSS values with custom properties, var() fallbacks, scoped overrides, theme switching, and computed-value debugging.
CSS Selector Basics: Type, Class, ID, and When to Use Each
Type, class, and id selectors in CSS: how each one targets elements, what they look like, and when to reach for which.
HTML Spanning Cells: colspan and rowspan
Use colspan and rowspan to let one HTML table cell cover several columns or rows, and keep the grid math straight so columns stay aligned.
CSS Specificity: How the Cascade Picks the Winning Rule
How CSS specificity is calculated and how the cascade resolves conflicts: the id, class, and type tiers, source order, and why !important bites back.
HTML Links and Images: href, src, alt, and Lazy Loading
Anchor elements with href for navigation and img elements with src and alt for pictures: the two elements that connect and illustrate a page.
Programming Learning Paths
Ordered programming learning paths for PHP, SQL, APIs, browser projects, and future language tracks.
HTML Table Structure: table, tr, td, and the Grid Model
The table, tr, and td elements and the grid model: how rows and cells nest to form columns automatically in an HTML table.
CSS Layout
How CSS arranges boxes on the page: normal flow, flexbox for one axis, grid for two, and positioning to lift elements out of flow.
CSS Colors and Units: Hex, RGB, Rem, Em, and Viewport Units
Write colors with keywords, hex, rgb, and hsl, including slash-alpha syntax, then choose between px, rem, em, percentage, and vw units.
Typography and Color in CSS
Learn CSS typography and color through color formats, length units, font and text properties, custom properties, and shadows.
CSS Pseudo-classes: Hover, Focus, nth-child, and States
CSS pseudo-classes like :hover, :focus, and :nth-child(): how they match elements by state and position without extra classes in your markup.
CSV to HTML Table: Parse, Preview & Render
Load a CSV file in the browser, parse it correctly, render a real accessible table, and follow the path into SQL when the preview becomes an import.
CSS Display and Normal Flow: Block, Inline, Inline-Block
How the display property and normal flow work: block, inline, and inline-block boxes, and the default way the browser stacks content.
CSS Selectors
How CSS selectors target elements: type, class, and id selectors, combinators, pseudo-classes, and how specificity decides which rule wins.
HTML Headings and Text: h1–h6, Paragraphs, and Emphasis
Headings h1 through h6, paragraphs, strong and em for emphasis, and line breaks: the elements that carry the words on an HTML page.
CSS Shadows: Box-Shadow, Text-Shadow, Drop-Shadow Effects
Create CSS shadows with box-shadow, text-shadow, and drop-shadow(), including layered, inset, and shape-aware effects.
CSS Combinators: Descendant, Child, and Sibling Selectors
Descendant, child, and sibling combinators in CSS: how the space, the child symbol, and the sibling symbols target elements by relationship.
PHP Configuration: php.ini, FPM, and Per-Directory Files
Control PHP behavior through php.ini, scanned INI files, FPM or Apache settings, per-directory files, and careful script-level overrides.
Processing XML with PHP
Parse XML in PHP with SimpleXML for small documents, XMLReader for large feeds, and safer defaults for untrusted input.
The Terminal: A Practical Guide
Learn how terminals and shells work, navigate files, use core Unix commands, connect commands with pipes, and supervise terminal-based coding agents.
Form and Spelling Validation in PHP
Validate PHP form input with browser hints, server-side rules, CSRF tokens, database constraints, and a realistic spellcheck boundary.
SQL UNION and UNION ALL: Combine Compatible Result Sets
Use SQL UNION and UNION ALL to combine compatible result sets without confusing them with joins.
SQL Transactions and ACID
Understand transactions, commits, rollbacks, and the ACID model for reliable database writes.
Build a Mini Chat App with PHP
Modernize the old PHP mini-chat pattern with PDO, sessions, CSRF protection, escaped output, and a clear polling or SSE boundary.
Sending Email in PHP
Modernize legacy PHP email tutorials around SMTP, attachments, header safety, deliverability, and when to avoid direct mail().
HTML Document Structure: Doctype, Head, Body, and Viewport
The doctype, the html, head, and body skeleton, plus the charset and viewport meta tags every HTML page needs before content.
Streaming Media with PHP
Use PHP to authorize protected MP3 and media access without pretending browser playback can make a full file impossible to download.
PHP Email Validation
Validate email-address shape in PHP with filter_var, then separate syntax checks from confirmation, deliverability, and account ownership.
Using Sockets in PHP
Use PHP streams and sockets for network clients, raw protocol work, and long-running services without copying old blocking socket habits.
Sending SMS with HTTP APIs
Modernize the old CodeWalkers SMS-over-HTTP pattern around provider APIs, consent, status callbacks, retries, and safe logging.
HTML Lists: Unordered, Ordered, and Description List Markup
Unordered, ordered, and description lists in HTML: the ul, ol, li, dl, dt, and dd elements, with small valid examples of each.
CSS Fonts and Text: Family, Size, Weight, and Line Height
Style readable text with font-family stacks, size, unitless line height, weight, spacing, web-font fallbacks, and text wrapping.
Build a Custom API with PHP
Finish the PHP web-app path with a small JSON API, HTTP methods, status codes, validation, PDO, and an OpenAPI-ready contract.
Build Dynamic Sites with PHP and MySQL
Start the PHP web-app path with one small dynamic site, a clean data model, PDO queries, and plain request handling.
Composite Images with PHP and GD
Use PHP and GD to place a logo, watermark, badge, or foreground PNG over a source image and save the merged result as a real file.
PHP Conditionals and Control Flow
Use if, elseif, switch, and match in PHP without letting loose comparisons or fallthrough hide bugs.
Terminal Commands: A Practical Reference
Look up common terminal commands by task, with concise explanations, copyable examples, expected output, and practical debugging notes.
Add News and Comments with PHP and MySQL
Extend a small PHP/MySQL app with news posts, comments, simple moderation, PDO writes, and escaped output.
PHP Security Fundamentals
Secure ordinary PHP surfaces with current password hashing, sessions, CSRF tokens, output escaping, prepared statements, and upload controls.
PHP OOP for Beginners
Learn the PHP object-oriented programming shape that still matters in 2026: classes, methods, constructors, repositories, and the limits of inheritance.
Import CSV into SQL: Load, Validate, and Transaction Paths
Move CSV data into MySQL, PostgreSQL, SQLite, or a PHP/PDO import flow without losing validation, transactions, or schema discipline.
Create Image Thumbnails with PHP
Generate thumbnail files with PHP and GD, keep uploaded paths safe, preserve aspect ratios, and hand the browser real thumbnail assets.
CSS Positioning: Static, Relative, Absolute, Fixed, Sticky
How the position property works: static, relative, absolute, fixed, and sticky, and how each one relates to normal flow and scrolling.
SQL Schema Design: Keys, Constraints, Indexes, Migrations
Design relational tables through a worked normalization example, then add stable keys, constraints, indexes, and safe migrations.
PHP and MySQL with PDO
Use PDO prepared statements to connect PHP to MySQL safely and keep SQL input handling clear.
Replit Guide: Vibe Coding Platform, Workflows, and Limits
A 2026 guide to Replit and its AI Agent: the vibe-coding platform that looks most like a real development environment, with a full browser IDE, Agent mode, cloud hosting, and a strong mobile app for building on the go.
Working with Text Files in PHP
Read, write, append, lock, and stream text files in PHP without copying old unsafe file-handling habits.
NuGet Packages for ASP.NET Core
A current ASP.NET Core package shortlist: what to add from NuGet, what is already in Microsoft.AspNetCore.App, and which packages belong in production apps.
SQL Indexes and Query Optimization
Learn what SQL indexes do, what they cost, and how to use EXPLAIN without guessing.
Smart Auto Refresh with PHP
Build a PHP endpoint that tells the browser when data changed, returns small JSON deltas, and avoids full-page refreshes for chat boxes, dashboards, and status panels.
Add a Poll to Your Website (HTML, CSS & JS)
Build an accessible poll with semantic HTML, progressive JavaScript results, server-side validation, and duplicate-vote handling.
PostgreSQL: Roles, JSONB, Indexes, Backups, and Upgrades
Learn where PostgreSQL fits, how roles and schemas separate access, how JSONB works with indexes, and how to plan backups and major upgrades.
Server Statistics and Observability
Replace old PHP uptime scripts with useful server statistics: metrics, logs, traces, browser timing, and alerts that explain production behavior.
Recursion in PHP
Understand recursion in PHP with base cases, stack limits, tree traversal, memoization, cycle guards, and the point where iteration is safer.
SQL Joins: Inner, Left, Self Joins, and Explicit Syntax
Understand inner joins, left joins, self joins, and why explicit JOIN syntax makes SQL easier to review.
MySQL: Restricted Users, InnoDB, Backups, and Major Upgrades
Learn where MySQL fits, how to create a restricted application user, how InnoDB transactions work, and how to plan backups and upgrades.
PHP Pagination with Previous and Next Links
Build previous and next links in PHP with validated page numbers, PDO queries, LIMIT/OFFSET, and a clear path to cursor pagination.
Writing a Template System in PHP
Build a small PHP template renderer with includes, output buffering, escaping, and path safety before deciding whether you need Twig, Blade, or a framework.
Server Contingency Planning
Build a server contingency plan around impact, backups, restore tests, rollback paths, ownership, and maintenance.
SQLite: CLI Inspection, WAL Mode, Backup, and Migration
Learn where SQLite fits, how to inspect a database with the CLI, what WAL changes, and how to back up and migrate a single-file database.
HTML Table Headers and Captions
Use th, thead, tbody, tfoot, caption, and the scope attribute to label an HTML table so browsers and screen readers understand its rows and columns.
Storing Images in a Database
Compare database BLOBs with external image storage through transaction, delivery, backup, memory, security, and cleanup requirements.
CSS Flexbox: One-Dimensional Layout
How flexbox arranges items along one axis: the flex container, the main and cross axis, and the justify-content and align-items properties.
Using AI Coding Agents in the Terminal
Learn how to start terminal AI coding agents in the right project, supervise commands, review file changes, and set safe working boundaries.
The LAMP Stack Explained
What the LAMP stack is, why Linux, Apache, MySQL or MariaDB, and PHP still run so much of the web, and when to reach for it.
Add Search to a PHP and MySQL App
Extend the PHP web-app path with prepared search queries, pagination, indexed SQL, and a clean upgrade path to full-text search.
MariaDB: MySQL Compatibility, Engines, and Config Files
Understand MariaDB's relationship to MySQL, current release model, storage engines, install/config differences, and when a PHP or SQL project should consider it.
Squid Caching Proxy
Understand what Squid still does well, where HTTP caching has moved, and how to think about proxies without treating cache as magic.