JS给数字加逗号

function toThousands(number) {
 let arr = String(number).split('.');
 let num = arr[0];
 let len = Math.ceil(num.length / 3) * 3;
 let result = num.padStart(len, '0').match(/\d{3}/g).join(',').replace(/^0+/, '');
 return arr[1] ? result + '.' + arr[1] : result;
}