如何格式化浮点数，最多保留“ n”个小数位而不会尾随零

Question

How to format number in JavaScript like c# as 0.#### ?

I use function .toFixed(4) but It's format 0.0000

var x = a / b;
console.log(x.toFixed(4));

I want to format like this...

1.0000 -> 1

1.2000 -> 1.2

1.2300 -> 1.23

1.2340 -> 1.234

1.2345 -> 1.2345

1.23456... -> 1.2346

Answer 1

Combine Number.prototype.toFixed() with a small RegExp replacement

console.log(x.toFixed(4).replace(/\.?0+$/, ''))

 const nums = ['1.0000', '1.2000', '1.2300', '1.2340', '1.2345', '1.23456'] const rx = /\\.?0+$/ nums.forEach(num => { console.info(num, ' -> ', parseFloat(num).toFixed(4).replace(rx, '')) }) 

Answer 2

The toFixed() method formats a number using fixed-point notation.

toFixed won't give you result in such format, you can change the values after decimal using regex

 let a = 4 let b = 3 let x = ( a / b ).toFixed(4) console.log(x.replace(/\\.(.*)$/g,(match,g1)=>{ return `.${g1 ? '#'.repeat(g1.length) : ''}` })); 

Update

 let a = 4 let b = 3 let changedFormat = (a,b) => { return ( a / b ).toFixed(4).replace(/\\.?0+$/g, '') } console.log(changedFormat(a,b)) console.log(changedFormat(1,1)) console.log(changedFormat(6,4))