今日已更新 111 条资讯 | 累计 32441 条内容
关于我们

标签：#p

找到 13442 篇相关文章

AI 资讯

TypeScript Generic Constraints in Depth: `extends`, `keyof`, and the Patterns That Prevent Runtime Errors

TypeScript Generic Constraints in Depth: extends , keyof , and the Patterns That Prevent Runtime Errors This article was written with the assistance of AI, under human supervision and review. Most TypeScript runtime errors stem from unconstrained generics that accept anything and crash on nothing. Teams write function get<T>(obj: T, key: string) and ship code that compiles cleanly but throws Cannot read property 'undefined' of undefined in production. The compiler stays silent because the generic accepts any type and the key accepts any string—no constraint exists to prove the key belongs to the object. Generic constraints solve this by restricting what types a generic parameter can accept. The extends keyword establishes a boundary—the generic must satisfy a specific shape. The keyof operator extracts valid keys from that shape. Together they form a type-level contract that makes illegal property access unrepresentable. The corrected signature function get<T, K extends keyof T>(obj: T, key: K): T[K] proves at compile time that key exists on obj , eliminating the entire class of property-access errors. This distinction is critical. Unconstrained generics provide no safety beyond what any offers. Constrained generics encode domain rules directly into the type system, shifting entire categories of bugs left from runtime to compile time. The patterns that follow demonstrate how production codebases use extends and keyof to build type-safe APIs that fail fast during development instead of silently in production. Key Takeaways Generic constraints with extends restrict type parameters to specific shapes, preventing the compiler from accepting types that would cause runtime failures. The keyof operator extracts object keys as a union type, enabling type-safe property access when combined with extends keyof constraints. Combining T extends SomeType with K extends keyof T creates a compile-time proof that a key exists on an object, eliminating property-access errors. Conditi

2026-07-19 原文 →
AI 资讯

How I Let an AI Agent Save a Draft on DEV

Reading a public website and changing something inside a signed-in account are not the same kind of job. I wanted an AI agent to collect the first 10 Hacker News stories, explain how it gathered them, and place that work inside my DEV editor. Save the article as a draft. Do not publish it. The hard part was not finding the stories. It was giving the agent enough access to finish inside my signed-in account without giving it permission to publish. That instruction contained two jobs with different access needs: Read public data from Hacker News. Change private account state by creating a draft in my signed-in DEV account. Using a full browser for the first job would add machinery and access that the result did not need. The public fetch path had neither the authenticated context nor the authority required for the second job. The useful question was not “Which browser tool should do everything?” It was “Where does this task actually cross into a browser?” Disclosure: I work on Unchained, SearchAgentSky, and Unbrowser. This article was prepared with AI assistance and reviewed before publication. The public step needed only fetch I initially opened Hacker News in a lightweight page session and queried its story links. It worked—but that did not mean it was necessary. Hacker News has a public API . The same result could be produced with ordinary HTTP: const base = " https://hacker-news.firebaseio.com/v0 " ; const ids = await fetch ( ` ${ base } /topstories.json` ). then ( r => r . json ()); const stories = await Promise . all ( ids . slice ( 0 , 10 ). map ( async ( id , index ) => { const story = await fetch ( ` ${ base } /item/ ${ id } .json` ). then ( r => r . json ()); return { rank : index + 1 , title : story . title , url : story . url ?? `https://news.ycombinator.com/item?id= ${ id } ` }; })); console . log ( JSON . stringify ( stories , null , 2 )); At 2026-07-19T03:19:04Z , the page query returned 30 Hacker News story anchors. At 2026-07-19T03:35:29.670Z , fetch

2026-07-19 原文 →
科技前沿

OPERATING SYSTEM

**🙄 فى كتاب chapter الصدمة دي هي بالظبط اللي حسيت بيها وأنا بقرأ أول “operating system: three easy Pieces “ ‘OSTEP’. 🖤اهلا بيكم ! يارب تكونوا بخير 💯 حابه اشارك معاكم رحلتى مع قراءة الكتاب ونستفيد منه سوا قبل ما نعرف هو !!!! ولا لا OS is virtual machine 🤔 !!!!دا يعنى ايه ووظيفته ايه OS تعالوا الاول نعرف ال موجودة فى الكمبيوتر ولا لا ؟؟؟؟ RAM وال CPUزى ال HARDWARE وهل هو قطعة ::هنبدأ من الاخر موجود على الكمبيوتر SW هو عبارة عن HW يسيدى مش قطعة OSال .على الجهازINSTALL ولازم يبقى ووظيفته ايه؟؟؟ OS طب يعنى ايه ‘OS’ اختصار “OPERATING SYSTEM”. .“يعنى نظام تشغيل “ .👁‍🗨👁‍🗨 تعالوا نعرف معنى ” نظام تشغيل” ونفسرها نظام تشغيل يعنى مسئول عن 1_ “HWالنظام “من غيره مش هيبقى فيه نظام خصوصا لقطع ال . يعنى بناخد منه الاذن للعمليات HW ببعضه وكمان بيدير ال HWيعنى هو بيربط ال 👏 . (Order)من الاخر بيخلق “النظام” 2_.”التشغيل “هو المسئول عن تشغيل البرامج Learn about Medium’s values هو اللي بيتحكم في دورة حياة البرنامج بالكامل؛هو اللي بيبدأ تشغيله في الذاكرة،OSيعني الـ وبيحدد هو محتاج إيه من إمكانيات الجهاز عشان يشتغل بكفاءة وبيفضل مراقبه ويحميه طول ما هوشغال ، ولحد ما تقفليه بنفسك 🌹 .ويقوم هو بتنظيف الذاكرة وتوفير المساحة لغيره 🧐::وظيفته بقا بيخلي البرنامج يشتغل بسهولة:1️⃣ لأنه بيخلق للبرنامج بيئة وهمية مريحة، وبيخفي عنه كل التعقيدات والأسلاك بتاعة الهاردوير عشان يشتغل بسلاسة 2️⃣: بيسمح للبرامج إنها تشارك الذاكرة بين كل البرامج بالعدل RAM بيشتغل كعسكري مرور بيوزع مساحة الـ . وبيحمي كل برنامج في مساحته الخاصة 3️⃣: بيمكن البرامج إنها تتعامل مع الأجهزة بيعمل كـ “وسيط” أو مترجم بيوصل كود البرنامج بالقطع الحقيقية (زي الشاشة أو الهارد) .عشان ينفذ أوامره فوراً بيعمل التلات حاجات دول إزاي في نفس الوقت وبمنتهى السلاسة؟ ؟؟؟OS طب الـ بيعملهم يسيدى عن طريق أكبر خدعة سحرية في عالم الكمبيوتروهي الـ Virtualization👌 كنت حابة جداً أكلمكم المرة دي عن خدعة الـ “Virtualization” 💎 😌👁👁اللي اتكلمنا عليها في العنوان، بس لقيت البوست هيبقى طويل أوي عليكم ✔🔥!!وعشان متعبكمش معايا.. هنخليها للبوست الجاي إن شاء الله 💯✅!!بيعمل الخدعة دي إزاي OSاستنوا البوست الجاى عشان نعرف الـ 💋.دمتم بخير **

2026-07-19 原文 →
开发者

Beyond Happy Path Engineering: Time

Clock drift, deadline mismatches, retries, and TTL behavior keep causing real incidents. Network companion: https://blog.gaborkoos.com/posts/2026-07-01-Beyond-Happy-Path-Engineering-the-Network/ submitted by /u/OtherwisePush6424 [link] [留言]

2026-07-19 原文 →
AI 资讯

US Marshals arrest the Tate brothers in Miami

The manosphere influencers Andrew and Tristan Tate were arrested Saturday in Miami by US Marshals in relation to new rape and sex trafficking charges in England. According to the Associated Press, British authorities are seeking the brothers' extradition. The new charges facing Andrew Tate include seven counts of rape, three of sex trafficking, three counts […]

2026-07-19 原文 →
← 上一页 下一页 →