TLDR Index
TLDR Web Dev

TLDR WEB DEV 2025-07-04

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01ARTICLES & TUTORIALS

WHAT'S THE DIFFERENCE BETWEEN ORDINARY FUNCTIONS AND ARROW FUNCTIONS IN JAVASCRIPT?

JavaScript has three ways to create functions: function declarations, function expressions, and arrow functions. The main differences are that arrow functions are more concise (using `=>` syntax) and don't have their own bindings to `this`, making them behave differently when used as object methods. Arrow functions also cannot be used as constructors with the `new` keyword, unlike regular functions, which can serve as constructor functions in older JavaScript patterns.

jrsinclair.com8 min read

COLOCATING AGENT INSTRUCTIONS WITH ENG DOC

Putting agent instructions within existing engineering documentation can avoid information duplication. After doing so, this method was tested with the Gemini CLI AI agent, which successfully followed instructions to convert a code example into a buildable and testable component.

technicalwriting.dev25 min read

NEXT.JS PROMISE RACING

"Promise racing" is where the server waits for a promise to resolve unless it takes longer than a specified timeout (in this case, 1 second). If the promise resolves quickly, the data is sent directly to the client without any loading state, but if it takes too long, a loading spinner is shown while the promise continues resolving on the client side. This provides performance benefits by avoiding unnecessary loading states for fast requests while still gracefully handling slower ones.

playfulprogramming.com2 min read

02OPINIONS & ADVICE

FLOUNDER MODE

The "Hollywood style" of pursuing various creative endeavors conflicts with the Silicon Valley pressure to achieve unicorn status through a single company. However, a joyful, interest-driven approach to work can be both fulfilling and impactful. It's also important to resist pressures at first to find your strengths and interests.

joincolossus.com20 min read

YOU ARE WHAT YOU LAUNCH: HOW SOFTWARE BECAME A LIFESTYLE BRAND

Software has transitioned from being purely functional to becoming a form of self-expression and a lifestyle brand. The apps people choose, like Notion and Obsidian, signal taste and align them with specific tribes or identities. Companies are now focusing on aesthetics and vibes in addition to functionality, creating tools that reflect and reinforce a curated image.

omeru.bearblog.dev9 min read

03LAUNCHES & TOOLS

PENNYBASE

Pennybase is a lightweight, file-based Backend-as-a-Service written in Go, with core backend features like a REST API, authentication, RBAC, and real-time updates, all without external dependencies. It stores data in CSV files with schema definitions for JSON mapping and uses an in-memory index for faster lookups.

github.comGitHub repository

04MISCELLANEOUS

FREQUENTLY ASKED QUESTIONS (AND ANSWERS) ABOUT AI EVALS

This is a comprehensive overview of how to evaluate LLMs, with practical advice and opinions. For example, it's better to build custom annotation tools for faster iteration instead of using off-the-shelf options. Also, it's better to use binary pass/fail evaluations over Likert scales for clearer LLM thinking.

hamel.dev30 min read

TOOLS: CODE IS ALL YOU NEED

Instead of relying heavily on MCP for automation, it's better for LLMs to generate code that can then be executed and validated. LLMs are currently better at writing tool-use code where the code is meant to call other tools through APIs.

lucumr.pocoo.org12 min read