Duncan Leung

How the browser turns CSS changes into pixels - the five stages of the render pipeline, why some CSS properties trigger the full pipeline and others skip most of it, and how to avoid jank by understanding which path your changes take.

Exploring effective programming education through mental models, with practical strategies for building conceptual understanding and improving outcomes.

A detailed guide to implementing dynamic locale selection in Gatsby using Contentful, GraphQL variables, and React Context for internationalized content.

A single-rule mental model for JavaScript's `this` - everything desugars to `Function.prototype.call(thisValue, ...args)`.

A guide to using TypeScript type guards for runtime type checking and type narrowing in your TypeScript applications.

A guide to properly handling array map operations with union types in TypeScript, including type inference and type safety considerations.

A guide to managing Python environment variables using dotenv, including best practices for configuration and security.

Python's with statement compresses try/finally resource handling into a clean syntax - but it's just sugar over the __enter__/__exit__ protocol, which you can implement yourself with a class or the @contextmanager decorator.

A practical guide to reading Python tracebacks - the bottom-up mental model, multi-frame call stacks, common exception types, and the "During handling of the above exception" chain that confuses beginners.

A detailed guide to testing React Helmet document head meta tags using React Testing Library, including setup, best practices, and common testing patterns.

A guide to implement TypeScript generics and conditional types for type-safe Emotion components with dynamic as props, including practical patterns and examples.

Most serverless bugs don't live in your code - they live at integration points and in IAM config.

Two practical patterns for scoping down the IAM permissions used by the Serverless Framework CLI when deploying - bottom-up gradual scoping, and the top-down 'dedicated deployer' pattern using a dev account as a permission discovery sandbox.

A practical cheatsheet for the Serverless Framework CLI - organized by workflow phase (bootstrap, develop, deploy, invoke, inspect, rollback, remove) instead of alphabetically.

AWS docs call Lambda-to-Lambda invocation an anti-pattern, but there are specific cases where direct invoke is the right call.

The mental model behind CloudFormation !

Bridging callback-style AWS SDK v2 methods with async/await in Node.js Lambda handlers - the .promise() method, sequential and parallel SDK calls, and the init-outside-handler pattern for cached Promises.

A deep dive into TypeScript ESLint plugin performance issues, exploring common bottlenecks and providing solutions for improved linting speed.

A practical guide to reducing AWS Lambda cold start latency in Node.js - the anatomy of a cold start, six concrete optimizations from SDK tree-shaking to HTTP keep-alive, common myths (VPC and Layers), and when to reach for Provisioned Concurrency.

A guide to set up ESLint, explaining the differences between ESLint config files and plugins, with detailed configuration examples and best practices.

A detailed guide to profiling, measuring, and optimizing slow ESLint rules, with practical techniques for improving linting performance.

A guide to create TypeScript module declarations for SVG and image assets, including webpack configuration and type definitions.

A guide to properly typing and integrating AWS Amplify configuration files in TypeScript projects, with focus on aws-exports.js setup.

A guide to configure React-Intl Provider decorators in Storybook for internationalization testing, including setup and best practices.

A guide to implementing Emotion Theme Provider decorators in Storybook, including troubleshooting common issues and best practices for theme management.

A detailed guide to setting up Webpack loaders in Storybook for importing and using SVG files as React components.

A guide to configure Emotion CSS prop with JSX Pragma in Storybook, including setup, troubleshooting, and best practices.

A step-by-step guide to keeping your Git fork in sync with the original upstream repository, including remote tracking and branch management.

A detailed guide to testing Formik form validation schemas using Jest and React Testing Library, covering validation rules, error handling, and test patterns.

An in-depth explanation of the __name__ == __main__ pattern in Python, why it exists, and how to use it effectively in your modules.

A guide to set up a modern Python development environment using pyenv for version management and Poetry for dependency management.

A practical guide to diagnosing and resolving common Netlify build failures, including deployment issues and continuous integration troubleshooting.

Recap of the Hacktoberfest Orange County meetup: open source contributions, community engagement, and collaborative coding experiences.

A detailed guide to testing Formik form submission handlers using Jest and React Testing Library, including async submissions and validation testing.

Understand and resolve React synthetic event warnings in setState, with best practices for event handling and state updates.

A deep dive into React pure render optimization and method binding patterns, exploring different approaches for improving component performance.

A guide to configuring Webpack for building optimized React production bundles on Windows, including environment-specific settings and common pitfalls.

A guide to avoiding common pitfalls when using setState in React, including asynchronous updates, batching, and state management patterns.