console格式化打印

MDN-Console

格式化打印

符号	描述
%o	打印javascript对象，可以是整数、字符串以及JSON数据
%d或%i	打印整数
%s	打印字符串
%f	打印浮点数

当要替换的参数类型和预期的打印类型不同时，参数会被转换成预期的打印类型。

for (var i=0; i<5; i++) {
  console.log("Hello, %s. You've called me %d times.", "Bob", i+1);
}
console.log("I want to print a number:%d","string")

// 输出
// Hello, Bob. You've called me 1 times.
// Hello, Bob. You've called me 2 times.
// Hello, Bob. You've called me 3 times.
// Hello, Bob. You've called me 4 times.
// Hello, Bob. You've called me 5 times.
// I want to print a number:NaN   

我们发现string字符串被转换成数字失败成转换成 NaN。

console定义样式

%c为打印内容定义样式

console.log("%cMy stylish message",
 "color: red; font-style: italic");

定义样式