Node.js console.time()方法
原文:https://www.geeksforgeeks.org/node-js-console-time-method/
console.time()方法是 Node.js 的控制台类，用于启动一个计时器，该计时器用于计算一段代码或函数所花费的时间。方法 console.timeEnd() 用于停止计时器，并将经过的时间(以毫秒为单位)输出到 stdout。计时器可以精确到亚毫秒。
语法
console.time( label )
参数:该方法接受单个参数标签作为参数可以在方法中传递，如果标签没有传递默认标签自动给方法。对于不同的功能或代码段，标签可以不同。
以下示例说明了 Node.js 中 console.time() 方法的工作原理:
例 1:
// Node.js program to demonstrate the
// console.time() method
// Sample function
function addCount() {
// Variable declaration
var sum = 0;
for (var i = 1; i < 100000; i++) {
// Adding i to the sum variable
sum += i;
}
// Return sum value
return sum;
}
// Starts the timer
console.time();
// Function call
addCount();
// Ends the timer and print the time
// taken by the piece of code
console.timeEnd();
输出:
default: 8.760ms
例 2:
// Node.js program to demonstrate the
// console.time() method
// Sample function
function addCount() {
// Variable declaration
var sum = 0;
for (var i = 1; i < 100000; i++) {
// Adding i to the sum variable
sum += i;
}
return sum; // returning sum
}
var timetaken = "Time taken by addCount function";
// Starts the timer. The label value is timetaken
console.time(timetaken);
addCount(); // function call
// Ends the timer and print the time
// taken by the piece of code
console.timeEnd(timetaken);
输出:
Time taken by addCount function: 7.380ms
示例 3: 该示例同时对不同的功能使用不同的标签。
// Node.js program to demonstrate the
// console.time() method
// Sample function
function addCount() {
var sum = 0; // Variable declaration
for (var i = 1; i < 100000; i++) {
sum += i; // Adding i to the sum variable
}
return sum; // returning sum
}
function countTime() {
var timetaken = "Time taken by addCount function";
// Starts the timer, the label value is timetaken
console.time(timetaken);
console.log(addCount()); // function call
// Ends the timer and print the time
// taken by the piece of code
console.timeEnd(timetaken);
}
var label2 = "Time taken by countTime function";
// Starts the timer, the label value is label2
console.time(label2);
countTime(); // function call
// Ends the timer and print the time
// taken by the piece of code
console.timeEnd(label2);
输出:
4999950000
Time taken by addCount function: 24.884ms
Time taken by countTime function: 25.928ms
参考:T2【https://nodejs . org/docs/latest-v 11 . x/API/console . html # console _ console _ time _ label
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