javascript 转换科学计数法，如何确定 10 次方后的数字

Question

If I type a number in the browser console the result is:

1000000000000000000000 --> 1e+21

0.00000000003453 --> 3.453e-11

I want to determine the number after e . In this example, the number is 21 or -11

Thanks!

Answer 1

You can convert the number to a string using .toExponential() and then split based on e and get the last element (which would be your number) like so:

 const getExp = n => +(n.toExponential().split('e').pop()) console.log(getExp(1000000000000000000000)) // 21 console.log(getExp(0.00000000003453)); // -11 console.log(getExp(0.000324)); // -4