为什么angular.isNumber（）不能按预期工作？ [英] Why is angular.isNumber() not working as expected?

问题描述

这看起来好像AngularJS的 angular.isNumber 不工作。它不与那些数字的字符串工作。难道我做错了什么？如果我只是用 isNaN（）？

It appears as if AngularJS's angular.isNumber is not working. It doesn't work with strings that are numbers. Am I doing something wrong? Should I just use isNaN()?

angular.isNumber('95.55') == false
angular.isNumber('95.55' * 1) == true
angular.isNumber('bla' * 1) == true
angular.isNumber(NaN) == true

我需要的东西，看看一个字符串是一个数字（当它实际上是）和 angular.isNumber（）不让我做，除非我乘以1，但如果我这样做那么它将永远是正确的。此外 NaN的不是数字（根据定义），因此应该返回false。

I need something to see if a string is a number (when it actually is) and angular.isNumber() won't let me do that unless I multiply by 1, but if I do that then it will always be true. Also NaN is not a number (by definition) and so should return false.

推荐答案

在的JavaScript 的的typeof NaN的==='号'。

如果您需要识别的字符串的作为的编号的，将其转换为的编号的，转换回的字符串和比较​​这对输入，例如。

If you need to recognise a String as a Number, cast it to Number, convert back to String and compare this against the input, for example.

function stringIsNumber(s) {
    var x = +s; // made cast obvious for demonstration
    return x.toString() === s;
}

stringIsNumber('95.55'); // true
stringIsNumber('foo'); // false
// still have
stringIsNumber('NaN'); // true

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