node.js - parseInt 和一元加运算，具体什么时候该用哪个的问题

Question

1. var x = parseInt("1", 10); // x === 1

2. var x = +"1"; // x === 1

我不知道上面两条的区别在哪里，但浏览器测试会发现，一元运算符明显要更快。再试一下，如果是字符串转换（不是数字），两个都会返回 NaN：

1. var y = parseInt("test" 10); // y === NaN

2. var y = +"test"; // y === NaN

所以在 Node.js 中，什么时候该用 parseInt 而不是一元加运算？希望大牛能讲一下其中的区别和原理。

Answer 1

parseInt can be used for base conversion.

Give an example of application: iconfont

Many websites that generate iconfonts will include hexadecimal font encoding when generating iconfonts, such as 'e800'
If you don't want to use the before pseudo-element to display the font, you can directly output the converted font encoding in the tag.

    String.fromCharCode(parseInt('\e800',16).toString(10))

You get the real font: ""

One-yuan plus can connect strings and perform type conversion.

Answer 2

In fact, they both convert strings into integers. The second one is fast because it directly performs bit operations. But parseInt is not. I personally think there is essentially no difference, and I prefer to use the second method for plastic conversion.