chrome下的测试结果:
修正方案:
<script>
Number.prototype.toFixed = function (n) {
if (n > 20 || n < 0) {
throw new RangeError('toFixed() digits argument must be between 0 and 20');
}
const number = this;
if (isNaN(number) || number >= Math.pow(10, 21)) {
return number.toString();
}
if (typeof (n) == 'undefined' || n == 0) {
return (Math.round(number)).toString();
}
let result = number.toString();
const arr = result.split('.');
// 整数的情况
if (arr.length < 2) {
result += '.';
for (let i = 0; i < n; i += 1) {
result += '0';
}
return result;
}
const integer = arr[0];
const decimal = arr[1];
if (decimal.length == n) {
return result;
}
if (decimal.length < n) {
for (let i = 0; i < n - decimal.length; i += 1) {
result += '0';
}
return result;
}
result = integer + '.' + decimal.substr(0, n);
const last = decimal.substr(n, 1);
// 四舍五入,转换为整数再处理,避免浮点数精度的损失
if (parseInt(last, 10) >= 5) {
const x = Math.pow(10, n);
console.log(x, parseFloat(result))
result = (Math.round((parseFloat(result) * x)) + 1) / x;
result = result.toFixed(n);
}
return result;
}
</script>