globalPreload()

警告:该钩子将在未来版本中删除。改用 initialize。当 hooks 模块具有 initialize 导出时,globalPreload 将被忽略。

\Warning: This hook will be removed in a future version. Use initialize instead. When a hooks module has an initialize export, globalPreload will be ignored.

• context <Object> 辅助预加载代码的信息

  \context <Object> Information to assist the preload code

  • port <MessagePort>

• 返回:<string> 应用启动前运行的代码

  \Returns: <string> Code to run before application startup

有时可能需要在应用运行所在的同一全局作用域内运行一些代码。此钩子允许返回在启动时作为宽松模式脚本运行的字符串。

\Sometimes it might be necessary to run some code inside of the same global scope that the application runs in. This hook allows the return of a string that is run as a sloppy-mode script on startup.

类似于 CommonJS 封装器的工作方式,代码在隐式函数范围内运行。唯一的参数是一个类似 require 的函数,可用于加载像 "fs" 这样的内置函数:getBuiltin(request: string)。

\Similar to how CommonJS wrappers work, the code runs in an implicit function scope. The only argument is a require-like function that can be used to load builtins like "fs": getBuiltin(request: string).

如果代码需要更高级的 require 功能,则必须使用 module.createRequire() 构造自己的 require。

\If the code needs more advanced require features, it has to construct its own require using module.createRequire().

export function globalPreload(context) {
 return `\
globalThis.someInjectedProperty = 42;
console.log('I just set some globals!');
const { createRequire } = getBuiltin('module');
const { cwd } = getBuiltin('process');
const require = createRequire(cwd() + '/<preload>');
// [...]
`;
} 拷贝

为预加载代码提供了另一个参数:port。这可以作为钩子的参数以及钩子返回的源文本的内部。此功能已移至 initialize 钩子。

\Another argument is provided to the preload code: port. This is available as a parameter to the hook and inside of the source text returned by the hook. This functionality has been moved to the initialize hook.

必须小心地正确调用 port.ref() 和 port.unref(),以防止进程处于无法正常关闭的状态。

\Care must be taken in order to properly call port.ref() and port.unref() to prevent a process from being in a state where it won't close normally.

/**
 * This example has the application context send a message to the hook
 * and sends the message back to the application context
 */
export function globalPreload({ port }) {
 port.onmessage = (evt) => {
 port.postMessage(evt.data);
 };
 return `\
 port.postMessage('console.log("I went to the hook and back");');
 port.onmessage = (evt) => {
 eval(evt.data);
 };
 `;
} 拷贝