Node.js process.hrtime()方法
原文:https://www . geesforgeks . org/node-js-process-HR time-method/
process.hrtime( )方法测量代码执行时间，返回包含当前高分辨率实时的数组，单位为[秒，纳秒]。我们通过提供第一个 process.hrtime()调用返回的时间作为第二个 process.hrtime()调用中的参数来度量代码执行时间。
process.hrtime()的优点是它测量时间非常精确，执行时间不到一毫秒。
语法:
process.hrtime([time])
参数:该方法接受如上所述和如下所述的单个参数。
- 时间:时间是一个可选参数 r，它必须是前一个进程的结果。hrtime()调用与当前时间的差值。
返回类型:返回一个包含 2 个整数的数组。该 1。 int 包含秒和 2。 int 纳秒。这些时间是相对于过去的任意时间，与一天中的时间无关。
例 1:
java 描述语言
// Implement the function..
var hrTime = process.hrtime()
// Time in millisecond...
console.log("Time in millisecond is: ", hrTime[0] * 1000 + hrTime[1] / 1000000)
输出:
Time in millisecond is: 218394926745.5
例 2:
java 描述语言
// Create a variable and call the process.hrtime() function.
var start_time = process.hrtime();
// Print the Start time:
console.log("Start Time:",start_time);
// Make the add function
setTimeout(function(){
// Create two variable
var a = '40',
b = '50';
// Print the Addition result:
console.log("Add of two number is :",(a - 0) + (b - 0));
// Create a variable and call the second process.hrtime()
// function and pass the start time as parameter.
var end_time = process.hrtime(start_time);
// Print the Execution time.
console.log("End Time:",end_time);
}, 1000);
输出:表示 1 秒，从开始到结束耗时 8779100 纳秒。
Start Time: [ 682340, 452477300 ]
Add of two number is : 90
End Time: [ 1, 8779100 ]
例 3:
java 描述语言
// Create a variable and call the process.hrtime() function.
var start_time = process.hrtime();
// Print the Start time:
console.log("Start Time:",start_time);
// Make the add function
setTimeout(function(){
console.log("Execution time will be calculated"+
" for printing this message....");
// Create a variable and call the second process.hrtime()
// function and pass the start time as.
var end_time = process.hrtime(start_time);
// Print the Execution time.
console.log("End Time:",end_time);
}, 1000);
输出:表示 1 秒，从开始到结束时间取 10987200 纳秒。
Start Time: [ 682865, 516565300 ]
Execution time will be calculated for printing this message....
End Time: [ 1, 10987200 ]
参考摄:https://nodejs . org/API/process . html # process _ process _ HR time _ time
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