Node.js process.uptime() 方法

process.uptime() 方法是 process 模块的内置应用程序编程接口，用于获取 Node.js 进程运行的秒数。

句法：

process.uptime();

参数：此方法不接受任何参数。

返回值：它返回一个浮点数，指定 Node.js 进程运行的秒数。

下面的例子说明了在 Node.js 中 process.uptime() 方法的使用：

示例 1：

// Node.js program to demonstrate the   
// process.uptime() Method
  
// Allocating process module
const process = require('process');
  
// Printing the number of seconds
// the Node.js process is running
console.log(process.uptime());

输出：

0.0842063

示例 2：

// Node.js program to demonstrate the   
// process.uptime() Method
  
// Allocating process module
const process = require('process');
  
// Checking whether the method
// exists or not
if (process.uptime) {
  
    // Printing uptime() value
    console.log("The number of seconds the"
          + " Node.js process is running: "
          + process.uptime() + " seconds");
  
    var i = 1000000;
  
    while(i--);
      
    console.log("The number of seconds the"
          + " Node.js process is running: "
          + process.uptime() + " seconds");
  
    console.log("In whole seconds: "
          + Math.floor(process.uptime())
          + " seconds");
}

输出：

the number of seconds the Node.js process is running: 0.077 seconds
the number of seconds the Node.js process is running: 0.087 seconds
In whole seconds: 0 seconds

注意：上面的程序将使用node filename.js命令编译和运行。

参考： https://nodejs.org/api/process.html#process_process_uptime