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Cosarty Technical Blog and Documentation

website·Indexed 30 days ago

https://www.cosarty.cn/

A collection of technical guides and articles covering frontend development, including Vue 3 hooks, React, TypeScript template strings, Electron screen recording, Prisma ORM schema and client configuration, and JavaScript binary data handling (Blob, ArrayBuffer). It also features insights on pnpm monorepos, esbuild production research, and CSS stacking contexts.

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What's inside Cosarty

  1. Overview of MongoDB Aggregation Methods

    MongoDB provides three primary ways to process data records and return computed results (such as averages or sums):

    1. Single-collection aggregation: Simple access to common aggregation processes operating on a single collection.
    2. Aggregation Pipeline: A data processing framework where documents pass through a multi-stage pipeline to be transformed into a final result.
    3. MapReduce: A two-stage process consisting of a 'map' phase (emitting objects for each input document) and a 'reduce' phase (combining the map outputs).

  2. Overview of Immer for immutable data management

    Immer is a JavaScript library that simplifies the handling of immutable data. It uses a 'copy-on-write' mechanism where changes are applied to a temporary draftState (a proxy of the currentState). Once changes are complete, Immer generates a new nextState based on those changes. This allows developers to write code that looks like it is mutating data while maintaining the benefits of immutability.

  3. Overview of React Class Component Lifecycle Phases

    React class components undergo two main phases during every state-driven view change: the render phase and the commit phase.

    1. Render Phase: React executes lifecycle hooks to determine what changes are needed. It performs the diffing algorithm to identify necessary DOM operations. Hooks executed here include constructor, getDerivedStateFromProps, shouldComponentUpdate, and render.
    2. Commit Phase: React applies the calculated DOM operations to the actual view. Hooks executed here include componentDidMount, componentDidUpdate, and componentWillUnmount.

    Note: Lifecycle methods are exclusive to class components because they create instances; functional components do not have these lifecycles.

  4. Understand vue-loader's SFC processing architecture

    vue-loader processes Single File Components (SFCs) using three main components: a normal loader (lib/index.js), a pitcher loader (lib/loaders/pitcher.js), and a plugin (lib/plugin.js).

    The processing happens in two stages:

    1. Preprocessing Stage: The VueLoaderPlugin extends the webpack configuration by injecting a 'pitcher' loader and cloning existing user rules. These cloned rules are modified to match specific SFC blocks using resourceQuery.
    2. Content Processing Stage: The normal loader and pitcher loader work together to transform the SFC content. The file is passed through loaders multiple times: first by the normal vue-loader, then by the pitcher loader for specific blocks (e.g., ?vue&type=script), and finally by the specific loaders defined in the user's webpack config (e.g., babel-loader or css-loader).

  5. Build CLI applications with cac

    cac is a lightweight JavaScript library for building CLI applications (e.g., adding subcommands like vite create). It is a smaller, zero-dependency alternative to commander or yargs, making it ideal for small to medium-sized CLI tools. Key APIs include cli.option, cli.version, cli.help, and cli.parse.

  6. Understand the fundamental differences between JavaScript Arrays and Objects

    Arrays and Objects in JavaScript differ in several key ways:

    1. Ordering and Naming: Arrays represent ordered collections of data without explicit names for elements; Objects represent unordered collections where data is accessed via named keys.
    2. Methodology: They utilize different sets of built-in methods.
    3. Uniqueness: Object keys must be unique, whereas array elements can be duplicated.
    4. Iteration: Objects do not have a length property and cannot be iterated with a standard for loop. Arrays have a default iterator allowing the use of for...of loops.
    5. Commonality: Both arrays and objects can be iterated using for...in loops.

  7. Understand how vue-loader extracts SFC blocks using resourceQuery

    vue-loader processes Single File Components (SFCs) by appending specific query parameters to the original file path. It then uses a selectBlock mechanism to identify which part of the SFC (template, script, style, or custom block) should be processed based on the query.type and query.index. This allows vue-loader to delegate specific content blocks to other specialized loaders (like less-loader for styles) by transforming the SFC content into a new import path, such as import xxx from '!-babel-loader!vue-loader?xxx'. This approach ensures that user-defined loader configurations are reused for each specific block type.
    module.exports = function selectBlock(
  descriptor,
  loaderContext,
  query,
  appendExtension
) {
  // template
  if (query.type === `template`) {
    if (appendExtension) {
      loaderContext.resourcePath += '.' + (descriptor.template.lang || 'html')
    }
    loaderContext.callback(
      null,
      descriptor.template.content,
      descriptor.template.map
    )
    return
  }

  // script
  if (query.type === `script`) {
    if (appendExtension) {
      loaderContext.resourcePath += '.' + (descriptor.script.lang || 'js')
    }
    loaderContext.callback(
      null,
      descriptor.script.content,
      descriptor.script.map
    )
    return
  }

  // styles
  if (query.type === `style` && query.index != null) {
    const style = descriptor.styles[query.index]
    if (appendExtension) {
      loaderContext.resourcePath += '.' + (style.lang || 'css')
    }
    loaderContext.callback(null, style.content, style.map)
    return
  }

  // custom
  if (query.type === 'custom' && query.index != null) {
    const block = descriptor.customBlocks[query.index]
    loaderContext.callback(null, block.content, block.map)
    return
  }
}

  8. Use picocolors for lightweight terminal styling

    picocolors is a lightweight alternative to chalk for adding colors and styles to terminal output. It is zero-dependency, significantly smaller (14x smaller than chalk), and faster (2x faster). It supports both CommonJS (CJS) and ECMAScript Modules (ESM). While it has a smaller feature set than chalk, it is sufficient for most custom tool requirements and is used by Vite.

  9. Monitor DOM element size changes with ResizeObserver

    The ResizeObserver API allows developers to precisely monitor the dimensions of specific DOM elements regardless of their level in the hierarchy. This is more efficient and accurate than listening to the global window.resize event, as element sizes can change independently of the viewport (e.g., due to dynamic content updates or CSS layout shifts).

  10. Resolve frontend routing issues for SPAs (Vue/React)

    In Single Page Applications, direct access to a route (e.g., /about) causes a 404 because Nginx looks for a physical file. To fix this, use try_files to check for the existence of the actual file/directory first, and fallback to index.html for all other requests.
    location / {
    root /data/www/ui;
    # Try the URI as a file, then as a directory, then as index.html
    try_files $uri $uri/ $uri/index.html $uri.html /index.html;
}

  11. Understand Docker core concepts: Images and Containers

    Docker is a tool for packaging, distributing, and deploying applications by virtualizing only the necessary runtime environment, making it more lightweight than traditional virtual machines.

    Key concepts:

    • Image: A read-only template (similar to a software installation package) used to create containers. It allows for easy distribution and installation.
    • Container: A runnable instance of an image. Each container provides an isolated and independent environment for the software to run.

  12. Understand CSS Stacking Context basics

    A Stacking Context is a logical model (similar to BFC) that defines a three-dimensional conceptualization of HTML elements along an imaginary z-axis. Elements within a stacking context are ranked by priority to determine their rendering order.

    Key characteristics:

    • Nesting: Stacking contexts can be nested; a stacking context element can contain other stacking contexts.
    • Independence: Stacking contexts are independent. The sorting rules for children of one stacking context do not affect children of another.
    • Default Priority: Stacking context elements generally have a higher default priority than non-stacking context elements (effectively a default z-index: 0).