console:count() 静态方法

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

console.count() 方法会记录调用 count() 的次数。

备注: 此特性在 Web Worker 中可用。

语法

js
count()
count(label)

参数

label 可选

一个字符串。如果给定,count() 会输出带有该标签的调用次数。如果未提供,调用 count() 的行为就像是带有“default”标签一样。

返回值

无(undefined)。

示例

例如,给定这样的代码:

js
let user = "";

function greet() {
  console.count();
  return `hi ${user}`;
}

user = "bob";
greet();
user = "alice";
greet();
greet();
console.count();

控制台输出看起来像这样:

"default: 1"
"default: 2"
"default: 3"
"default: 4"

标签显示为 default,因为没有提供明确的标签。

如果我们将 user 变量作为第一次调用 count() 函数时的 label 参数传入,并将字符串”alice“作为第二次调用的参数:

js
let user = "";

function greet() {
  console.count(user);
  return `hi ${user}`;
}

user = "bob";
greet();
user = "alice";
greet();
greet();
console.count("alice");

我们会看到如下的输出:

"bob: 1"
"alice: 1"
"alice: 2"
"alice: 3"

我们现在仅根据 label 的值维护单独的计数。

规范

Specification
Console
# count

浏览器兼容性

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
count() static method

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