Node.js 进程警告事件

“警告”是进程模块中的 Process 类事件，每当 Node.js 发出进程警告时就会发出该事件。

句法：

Event: 'warning'

参数：此事件不接受任何参数作为参数。

返回值：此事件只返回一个回调函数以供进一步操作。

示例 1：

index.js

// Node.js program to demonstrate the  
// Process 'warning' Event
  
// Importing process module
const process = require('process');
  
// Intentionally emitted warning
process.emitWarning('something strange happened');
  
// Event 'warning' 
process.on('warning', (warning) => {
   console.warn("warning name - " + warning.name);
   console.warn("warning message - " + warning.message);
});

使用以下命令运行index.js文件：

node index.js

输出：

(node:8004) Warning: something strange happened
(Use `node --trace-warnings ...` to show where
the warning was created)
warning name - Warning
warning message - something strange happened

示例 2：

index.js

// Node.js program to demonstrate the  
// Process 'warning' Event
  
// Importing process module
const process = require('process');
  
// Intentionally emitted warning
process.emitWarning('Running out of Storage');
  
// Event 'warning' 
process.on('warning', (warning) => {
  console.warn("warning stacktrace - " + warning.stack)
});

使用以下命令运行index.js文件：

node index.js

输出：

(node:13400) Warning: Running out of Storage
(Use `node –trace-warnings …` to show where the warning was created)
warning stacktrace – Warning: Running out of Storage
at Object. (F:\java\GFG.js:8:9)
at Module._compile (node:internal/modules/cjs/loader:1109:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1138:10)
at Module.load (node:internal/modules/cjs/loader:989:32)
at Function.Module._load (node:internal/modules/cjs/loader:829:14)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:76:12)
at node:internal/main/run_main_module:17:47

参考：https://nodejs.org/dist/latest-v16.x/docs/api/process.html#process_event_warning