Finding and Fixing Memory Leaks in JavaScript and React Apps

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A developer describes how a steadily climbing memory graph in DevTools revealed a leak that slowly degraded their app's performance. Memory leaks occur when forgotten references stop the garbage collector from freeing objects, and the usual culprits are unremoved event listeners, uncleared timers, fetches resolving after unmount, detached DOM nodes, unbounded caches, and third-party instances that are never destroyed. The article recommends a quick check using the Performance monitor's JS heap size to spot sustained growth. It then outlines a deeper workflow using heap snapshot comparisons, detached-node filtering, allocation sampling, and the React DevTools Profiler to identify components that mount and unmount excessively.

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OpenAI's always-on 'Dots' agents raise privacy and compute cost concerns

At its DevDay event on September 29, OpenAI introduced Dots, agents that run continuously in the cloud, each with its own computer and browser, and connect to many apps through plugins. Users can control when the agent acts alone or asks first, and sensitive actions such as changing passwords remain with the user. Critics such as Signal president Meredith Whittaker argue that deep access to personal data creates privacy and security risks, including exposure of third parties who never consented to an AI reading their messages. Because always-on agents are computationally expensive, OpenAI is also routing some work to a smaller, cheaper model, while companies report AI spending well above their budgets. Experts suggest granting access gradually and treating agent permissions as an architecture decision involving least privilege and cost controls.

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ProgrammingDEV Community ·

Rate limiting Minimal APIs in .NET with the built-in middleware

Public APIs are exposed to clients that may flood an endpoint with requests, whether from a bug, a faulty script or deliberate abuse. Since .NET 7, the framework includes rate limiting middleware, so no third-party package is needed. The article demonstrates a per-IP fixed-window policy that rejects excess requests immediately with a 429 status and a Retry-After header. It also covers applying the policy to specific endpoints, keeping health checks unlimited, and writing integration tests with WebApplicationFactory.

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ProgrammingDEV Community ·

DejaVu: AI incident agent uses long-term memory to recall past outage fixes

An engineer describes building DejaVu, an AI on-call agent designed to remember every outage a team has resolved. The author argues that most incidents are recurring failure patterns that appear under different service names and error messages, and that general chatbots lack the context to recognize them. DejaVu works through a recall, reason, and retain loop, using the Hindsight open-source memory system to retrieve semantically similar past incidents and feed them to an LLM. In a side-by-side test, the same model reported 20% confidence without memory versus 98% with memory for a simulated cache bug. The author notes that a keyword search would miss many of the 6 cache-related incidents in a 20-incident dataset, which semantic recall can surface.

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ProgrammingDEV Community ·

Four Remote MCP Servers Add Actions, Not Just Reports, for SEO and Slide Tools

A developer team describes shipping four remote Streamable HTTP MCP servers covering LinkDR, AI SEO Tracker, GenPPT, and Awesome Tools, so users can move from discovery to execution within a single chat session. They argue that many earlier MCP servers stop at diagnostic reads and leave users to finish tasks manually in a browser. To address this, each read-only diagnostic tool is paired with a write tool that changes state, such as creating projects, ordering backlinks, or exporting decks. The post also outlines the architecture for safely handling mutations and real payments, including a two-step spend confirmation gate to prevent accidental charges. The authors frame this design philosophy as "Outputmaxxing," meaning every tool should end in a concrete output or state change.

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