[英]Javascript casts floating point numbers to integers without cause
I wrote a function that behaves differently depending on the numeric type of it's parameters. 我写了一个函数,它的行为有所不同,具体取决于它的参数的数字类型。 Integer or float. 整数或浮点数。
Using some code from this question How do I check that a number is float or integer? 使用此问题中的一些代码如何检查数字是浮点数还是整数? it was easy to detect if float or not but then I stumbled upon the case that javascript casts 1.0
to 1
without cause if you call a function using that number. 很容易检测浮动与否,但后来我偶然发现javascript在没有原因的情况下将1.0
转换为1
情况,如果您使用该数字调用函数。
Example: 例:
function dump(a, b) {
console.log(a, typeof b, b);
}
dump('1', 1);
dump('1.0', 1.0);
dump('1.1', 1.1);
Output chrome, firefox, ie, opera and safari all gave the same result: 输出chrome,firefox,即opera和safari都给出了相同的结果:
1 number 1
1.0 number 1 "wrong"
1.1 number 1.1
I know that javascript only knows the type number
but that forced cast seems to go way overboard. 我知道javascript只知道类型number
但强制转换似乎过分了。 The only solution I came up with was to call the function using string values like '1.0'
, detect the dot and use parseFloat
or parseInt
. 我想出的唯一解决方案是使用字符串值(如'1.0'
调用函数,检测点并使用parseFloat
或parseInt
。
Any suggestion on that? 有什么建议吗?
You've acknowledged that JavaScript only has a single Number
type. 您已经承认JavaScript只有一个Number
类型。 As such, 1
is identical to 1.0
. 因此, 1
与1.0
相同。
If you need this for display purposes, then you should use toFixed
. 如果您需要这个用于显示目的,那么您应该使用toFixed
。
1..toFixed(1); // "1.0"
number%1===0
如果该条件为true
,则为整数,否则为浮点数
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