js-数字操作与功能实现-运用

1 数字末尾加万

function formatWan(n) {
  n = n.toString();
  if ( n < 10000) {
    return ( n / 10000 ).toFixed((5-n.length)) + '万';
  } else {
    return ( n / 10000 ).toFixed(1) + '万';
  }
}
console.log( formatWan(12345) ); // '1.2万'
console.log( formatWan(123) ); // '0.01万'
console.log( formatWan(1) ); // '0.0001万'

2 数字指定数位不足补零

Number.prototype.lenWithZero = function(oCount) {
            var strText = this.toString();
            while(strText.length < oCount) {
                strText = `0${strText}`;
            };
            return strText;
        }
        let num = 123;
        console.log(num.lenWithZero(5)); // '00123'