JavaScript數值千分位格式化的方法和效能

function format_with_array(number) {
var arr = (number + '').split('.');
var int = arr[0].split('');
var fraction = arr[1] || '';
var r = "";
var len = int.length;
int.reverse().forEach(function (v, i) {
if (i !== 0 && i % 3 === 0) {
r = v + "," + r;
} else {
r = v + r;
}
})
return r + (!!fraction ? "." + fraction : '');
}

function format_with_substring(number) {
var arr = (number + '').split('.');
var int = arr[0] + '';
var fraction = arr[1] || '';
var f = int.length % 3;
var r = int.substring(0, f);

for (var i = 0; i < Math.floor(int.length / 3); i++) {
r += ',' + int.substring(f + i * 3, f + (i + 1) * 3)
}

if (f === 0) {
r = r.substring(1);
}
return r + (!!fraction ? "." + fraction : '');
}

function format_with_mod(number) {
var n = number;
var r = "";
do {
mod = n % 1000;
n = n / 1000;
r = ~~mod + (!!r ? "," + r : "")
} while (n > 1)

var strNumber = number + "";
var index = strNumber.indexOf(".");
if (index > 0) {
r += strNumber.substring(index);
}
return r;
}

function format_with_regex(number) {
var reg = /\d{1,3}(?=(\d{3})+$)/g;
return (number + '').replace(reg, '$&,');
}

function format_with_regex(number) {
var reg = /(\d)(?=(?:\d{3})+$)/g
return (number + '').replace(reg, '$1,');
}

function format_with_toLocaleString(number, minimumFractionDigits, maximumFractionDigits) {
minimumFractionDigits = minimumFractionDigits || 2;
maximumFractionDigits = (maximumFractionDigits || 2);
maximumFractionDigits = Math.max(minimumFractionDigits, maximumFractionDigits);

return number.toLocaleString("en-us", {
maximumFractionDigits: maximumFractionDigits || 2,
minimumFractionDigits: minimumFractionDigits || 2
})
}

function format_with_Intl(number, minimumFractionDigits, maximumFractionDigits) {
minimumFractionDigits = minimumFractionDigits || 2;
maximumFractionDigits = (maximumFractionDigits || 2);
maximumFractionDigits = Math.max(minimumFractionDigits, maximumFractionDigits);

return new Intl.NumberFormat('en-us', {
maximumFractionDigits: maximumFractionDigits || 2,
minimumFractionDigits: minimumFractionDigits || 2
}).format(number)
}

function getData(count) {
var data = new Array(count).fill(0).map(function (i) {
var rd = Math.random();
var r = rd * Math.pow(10, 10);
if (rd > 0.5) {
r = ~~r;
}
return r
})
return data;
}

function test(data, fn, label) {
var start = performance.now();
for (var i = 0; i < data.length; i++) {
fn(data[i]);
}
var time = performance.now() - start;

message((fn.name || label) + ":" + time + "ms");
}


function executeTest() {
var data = getData(+textCount.value);
test(data, format_with_array);
test(data, format_with_mod);
test(data, format_with_substring);
test(data, format_with_regex);
test(data, format_with_toLocaleString);
test(data, format_with_Intl);
}

function message(msg) {
var el = document.createElement("p");
el.innerHTML = msg;
messageEl.appendChild(el);
}