Posted 2019-05-22Updated 2021-05-28Dev Notes

Set modules to false in babel

Version 2 of webpack supports ES6 modules syntax natively, meaning you can use import and export without a tool like babel to handle this for you.

So when we config babel-preset-env we can set “modules” to false, instead of using babel to compiling then into other module type.

Posted 2019-05-18Updated 2021-06-17Learning Notes

NodeJS poll phrase blocking logic

As mentioned in the NodeJS doc, in poll phrase, node will block when appropriate. This post will discuss the block conditions and why this phrase blocks as Node should perfom a non-blocking I/O operations.

There are several logics in libuv core.c

First is the uv_run function, which operates the process of entire event loop:

int uv_run(uv_loop_t* loop, uv_run_mode mode) {
  int timeout;
  int r;
  int ran_pending;

  r = uv__loop_alive(loop);
  if (!r)
    uv__update_time(loop);

  while (r != 0 && loop->stop_flag == 0) {
    uv__update_time(loop);
    uv__run_timers(loop);
    ran_pending = uv__run_pending(loop);
    uv__run_idle(loop);
    uv__run_prepare(loop);

    timeout = 0;
    if ((mode == UV_RUN_ONCE && !ran_pending) || mode == UV_RUN_DEFAULT)
      timeout = uv_backend_timeout(loop);

    uv__io_poll(loop, timeout);
    uv__run_check(loop);
    uv__run_closing_handles(loop);

    if (mode == UV_RUN_ONCE) {
      /* UV_RUN_ONCE implies forward progress: at least one callback must have
       * been invoked when it returns. uv__io_poll() can return without doing
       * I/O (meaning: no callbacks) when its timeout expires - which means we
       * have pending timers that satisfy the forward progress constraint.
       *
       * UV_RUN_NOWAIT makes no guarantees about progress so it's omitted from
       * the check.
       */
      uv__update_time(loop);
      uv__run_timers(loop);
    }

    r = uv__loop_alive(loop);
    if (mode == UV_RUN_ONCE || mode == UV_RUN_NOWAIT)
      break;
  }

  /* The if statement lets gcc compile it to a conditional store. Avoids
   * dirtying a cache line.
   */
  if (loop->stop_flag != 0)
    loop->stop_flag = 0;

  return r;
}

Posted 2018-10-15Updated 2021-06-17Dev Notes

Hexo Asset Folders

In root’s _config.yml, set post_asset_folder to true:

1	post_asset_folder: true

When you create a new post, hexo will generate an asset folder with the same name as the post.

To include assets in markdown:

1
2
3

{% asset_path slug %}
{% asset_img slug [title] %}
{% asset_link slug [title] %}

Examples:

1 2	{% asset_img example.jpg This is an example image %} {% asset_img "spaced asset.jpg" "spaced title" %}

Posted 2018-10-14Updated 2021-05-28Dev Notes

babel-polyfill and babel-runtime

Use @babel/runtime when you don’t want to pollute global namespace(e.g. you are building a library).

Install @babel/plugin-transform-runtime as development dependency.

1	npm install --save-dev @babel/plugin-transform-runtime

Install @babel/runtime as a production dependency.

1	npm install --save @babel/runtime

Use @babel/polyfill for writing an app.

Source: https://babeljs.io/docs/en/babel-plugin-transform-runtime

Set modules to false in babel

NodeJS poll phrase blocking logic

Hexo Asset Folders

babel-polyfill and babel-runtime

Categories

Tags

Archives

Recents