本文探讨了ECMAScript中一元加号操作符的功能与使用方法。一元加号对数值本身没有影响，但能将字符串转换为数值型。此外，文中还提到了jQuery源代码中的一元加号应用实例。
p36:
The unary plus and minus are familiar symbols to most people and operate the same way in
ECMAScript as they do in high school math. The unary plus essentially has no effect on a number:
var iNum= 25;
iNum = +iNum;
alert(iNum); //outputs “25”
In this code, the unary plus is applied to the number 25, which returns the exact same value. Although
unary plus has no effect on numbers, it has an interesting effect on strings: It converts them to numbers.
var sNum = “25”;
alert(typeof sNum); //outputs “string”
var iNum = +sNum;
alert(typeof iNum); //outputs “number”
这在jquery的src中有看到
The unary plus and minus are familiar symbols to most people and operate the same way in
ECMAScript as they do in high school math. The unary plus essentially has no effect on a number:
var iNum= 25;
iNum = +iNum;
alert(iNum); //outputs “25”
In this code, the unary plus is applied to the number 25, which returns the exact same value. Although
unary plus has no effect on numbers, it has an interesting effect on strings: It converts them to numbers.
var sNum = “25”;
alert(typeof sNum); //outputs “string”
var iNum = +sNum;
alert(typeof iNum); //outputs “number”
这在jquery的src中有看到
function now(){
return +new Date;
}
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