我想用JavaScript格式化价格。我想要一个函数，它将浮点作为参数，并返回如下格式的字符串：
"$ 2,500.00"
我该怎么做？
当前回答
这里有一些解决方案，都通过了测试套件。包括测试套件和基准测试。如果你想复制和粘贴来测试，试试这个要点。
方法0（RegExp）
它是基于VisioN的答案，但如果没有小数点，它会修复。
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0].replace(/\d(?=(\d{3})+$)/g, '$&,');
return a.join('.');
}
}
方法1
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.'),
// Skip the '-' sign
head = Number(this < 0);
// Skip the digits that's before the first thousands separator
head += (a[0].length - head) % 3 || 3;
a[0] = a[0].slice(0, head) + a[0].slice(head).replace(/\d{3}/g, ',$&');
return a.join('.');
};
}
方法2（拆分到阵列）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0]
.split('').reverse().join('')
.replace(/\d{3}(?=\d)/g, '$&,')
.split('').reverse().join('');
return a.join('.');
};
}
方法3（循环）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('');
a.push('.');
var i = a.indexOf('.') - 3;
while (i > 0 && a[i-1] !== '-') {
a.splice(i, 0, ',');
i -= 3;
}
a.pop();
return a.join('');
};
}
用法示例
console.log('======== Demo ========')
console.log(
(1234567).format(0),
(1234.56).format(2),
(-1234.56).format(0)
);
var n = 0;
for (var i=1; i<20; i++) {
n = (n * 10) + (i % 10)/100;
console.log(n.format(2), (-n).format(2));
}
分离器
如果我们需要自定义千位分隔符或小数分隔符，请使用replace（）：
123456.78.format(2).replace(',', ' ').replace('.', ' ');
测试套件
function assertEqual(a, b) {
if (a !== b) {
throw a + ' !== ' + b;
}
}
function test(format_function) {
console.log(format_function);
assertEqual('NaN', format_function.call(NaN, 0))
assertEqual('Infinity', format_function.call(Infinity, 0))
assertEqual('-Infinity', format_function.call(-Infinity, 0))
assertEqual('0', format_function.call(0, 0))
assertEqual('0.00', format_function.call(0, 2))
assertEqual('1', format_function.call(1, 0))
assertEqual('-1', format_function.call(-1, 0))
// Decimal padding
assertEqual('1.00', format_function.call(1, 2))
assertEqual('-1.00', format_function.call(-1, 2))
// Decimal rounding
assertEqual('0.12', format_function.call(0.123456, 2))
assertEqual('0.1235', format_function.call(0.123456, 4))
assertEqual('-0.12', format_function.call(-0.123456, 2))
assertEqual('-0.1235', format_function.call(-0.123456, 4))
// Thousands separator
assertEqual('1,234', format_function.call(1234.123456, 0))
assertEqual('12,345', format_function.call(12345.123456, 0))
assertEqual('123,456', format_function.call(123456.123456, 0))
assertEqual('1,234,567', format_function.call(1234567.123456, 0))
assertEqual('12,345,678', format_function.call(12345678.123456, 0))
assertEqual('123,456,789', format_function.call(123456789.123456, 0))
assertEqual('-1,234', format_function.call(-1234.123456, 0))
assertEqual('-12,345', format_function.call(-12345.123456, 0))
assertEqual('-123,456', format_function.call(-123456.123456, 0))
assertEqual('-1,234,567', format_function.call(-1234567.123456, 0))
assertEqual('-12,345,678', format_function.call(-12345678.123456, 0))
assertEqual('-123,456,789', format_function.call(-123456789.123456, 0))
// Thousands separator and decimal
assertEqual('1,234.12', format_function.call(1234.123456, 2))
assertEqual('12,345.12', format_function.call(12345.123456, 2))
assertEqual('123,456.12', format_function.call(123456.123456, 2))
assertEqual('1,234,567.12', format_function.call(1234567.123456, 2))
assertEqual('12,345,678.12', format_function.call(12345678.123456, 2))
assertEqual('123,456,789.12', format_function.call(123456789.123456, 2))
assertEqual('-1,234.12', format_function.call(-1234.123456, 2))
assertEqual('-12,345.12', format_function.call(-12345.123456, 2))
assertEqual('-123,456.12', format_function.call(-123456.123456, 2))
assertEqual('-1,234,567.12', format_function.call(-1234567.123456, 2))
assertEqual('-12,345,678.12', format_function.call(-12345678.123456, 2))
assertEqual('-123,456,789.12', format_function.call(-123456789.123456, 2))
}
console.log('======== Testing ========');
test(Number.prototype.format);
test(Number.prototype.format1);
test(Number.prototype.format2);
test(Number.prototype.format3);
基准
function benchmark(f) {
var start = new Date().getTime();
f();
return new Date().getTime() - start;
}
function benchmark_format(f) {
console.log(f);
time = benchmark(function () {
for (var i = 0; i < 100000; i++) {
f.call(123456789, 0);
f.call(123456789, 2);
}
});
console.log(time.format(0) + 'ms');
}
// If not using async, the browser will stop responding while running.
// This will create a new thread to benchmark
async = [];
function next() {
setTimeout(function () {
f = async.shift();
f && f();
next();
}, 10);
}
console.log('======== Benchmark ========');
async.push(function () { benchmark_format(Number.prototype.format); });
next();
其他回答
这里有一些解决方案，都通过了测试套件。包括测试套件和基准测试。如果你想复制和粘贴来测试，试试这个要点。
方法0（RegExp）
它是基于VisioN的答案，但如果没有小数点，它会修复。
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0].replace(/\d(?=(\d{3})+$)/g, '$&,');
return a.join('.');
}
}
方法1
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.'),
// Skip the '-' sign
head = Number(this < 0);
// Skip the digits that's before the first thousands separator
head += (a[0].length - head) % 3 || 3;
a[0] = a[0].slice(0, head) + a[0].slice(head).replace(/\d{3}/g, ',$&');
return a.join('.');
};
}
方法2（拆分到阵列）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('.');
a[0] = a[0]
.split('').reverse().join('')
.replace(/\d{3}(?=\d)/g, '$&,')
.split('').reverse().join('');
return a.join('.');
};
}
方法3（循环）
if (typeof Number.prototype.format === 'undefined') {
Number.prototype.format = function (precision) {
if (!isFinite(this)) {
return this.toString();
}
var a = this.toFixed(precision).split('');
a.push('.');
var i = a.indexOf('.') - 3;
while (i > 0 && a[i-1] !== '-') {
a.splice(i, 0, ',');
i -= 3;
}
a.pop();
return a.join('');
};
}
用法示例
console.log('======== Demo ========')
console.log(
(1234567).format(0),
(1234.56).format(2),
(-1234.56).format(0)
);
var n = 0;
for (var i=1; i<20; i++) {
n = (n * 10) + (i % 10)/100;
console.log(n.format(2), (-n).format(2));
}
分离器
如果我们需要自定义千位分隔符或小数分隔符，请使用replace（）：
123456.78.format(2).replace(',', ' ').replace('.', ' ');
测试套件
function assertEqual(a, b) {
if (a !== b) {
throw a + ' !== ' + b;
}
}
function test(format_function) {
console.log(format_function);
assertEqual('NaN', format_function.call(NaN, 0))
assertEqual('Infinity', format_function.call(Infinity, 0))
assertEqual('-Infinity', format_function.call(-Infinity, 0))
assertEqual('0', format_function.call(0, 0))
assertEqual('0.00', format_function.call(0, 2))
assertEqual('1', format_function.call(1, 0))
assertEqual('-1', format_function.call(-1, 0))
// Decimal padding
assertEqual('1.00', format_function.call(1, 2))
assertEqual('-1.00', format_function.call(-1, 2))
// Decimal rounding
assertEqual('0.12', format_function.call(0.123456, 2))
assertEqual('0.1235', format_function.call(0.123456, 4))
assertEqual('-0.12', format_function.call(-0.123456, 2))
assertEqual('-0.1235', format_function.call(-0.123456, 4))
// Thousands separator
assertEqual('1,234', format_function.call(1234.123456, 0))
assertEqual('12,345', format_function.call(12345.123456, 0))
assertEqual('123,456', format_function.call(123456.123456, 0))
assertEqual('1,234,567', format_function.call(1234567.123456, 0))
assertEqual('12,345,678', format_function.call(12345678.123456, 0))
assertEqual('123,456,789', format_function.call(123456789.123456, 0))
assertEqual('-1,234', format_function.call(-1234.123456, 0))
assertEqual('-12,345', format_function.call(-12345.123456, 0))
assertEqual('-123,456', format_function.call(-123456.123456, 0))
assertEqual('-1,234,567', format_function.call(-1234567.123456, 0))
assertEqual('-12,345,678', format_function.call(-12345678.123456, 0))
assertEqual('-123,456,789', format_function.call(-123456789.123456, 0))
// Thousands separator and decimal
assertEqual('1,234.12', format_function.call(1234.123456, 2))
assertEqual('12,345.12', format_function.call(12345.123456, 2))
assertEqual('123,456.12', format_function.call(123456.123456, 2))
assertEqual('1,234,567.12', format_function.call(1234567.123456, 2))
assertEqual('12,345,678.12', format_function.call(12345678.123456, 2))
assertEqual('123,456,789.12', format_function.call(123456789.123456, 2))
assertEqual('-1,234.12', format_function.call(-1234.123456, 2))
assertEqual('-12,345.12', format_function.call(-12345.123456, 2))
assertEqual('-123,456.12', format_function.call(-123456.123456, 2))
assertEqual('-1,234,567.12', format_function.call(-1234567.123456, 2))
assertEqual('-12,345,678.12', format_function.call(-12345678.123456, 2))
assertEqual('-123,456,789.12', format_function.call(-123456789.123456, 2))
}
console.log('======== Testing ========');
test(Number.prototype.format);
test(Number.prototype.format1);
test(Number.prototype.format2);
test(Number.prototype.format3);
基准
function benchmark(f) {
var start = new Date().getTime();
f();
return new Date().getTime() - start;
}
function benchmark_format(f) {
console.log(f);
time = benchmark(function () {
for (var i = 0; i < 100000; i++) {
f.call(123456789, 0);
f.call(123456789, 2);
}
});
console.log(time.format(0) + 'ms');
}
// If not using async, the browser will stop responding while running.
// This will create a new thread to benchmark
async = [];
function next() {
setTimeout(function () {
f = async.shift();
f && f();
next();
}, 10);
}
console.log('======== Benchmark ========');
async.push(function () { benchmark_format(Number.prototype.format); });
next();
另一种方式：
function centsToDollaString(x){
var cents = x + ""
while(cents.length < 4){
cents = "0" + cents;
}
var dollars = cents.substr(0,cents.length - 2)
var decimal = cents.substr(cents.length - 2, 2)
while(dollars.length % 3 != 0){
dollars = "0" + dollars;
}
str = dollars.replace(/(\d{3})(?=\d)/g, "$1" + ",").replace(/^0*(?=.)/, "");
return "$" + str + "." + decimal;
}
适用于所有当前浏览器
使用toLocaleString以货币的语言敏感表示形式格式化货币（使用ISO 4217货币代码）。
(2500).toLocaleString("en-GB", {style: "currency", currency: "GBP", minimumFractionDigits: 2})
avenmore的南非兰特代码片段示例：
console.log（（2500）.toLocaleString（“en-ZA”，｛style:“currency”，currency:“ZAR”，minimumFractionDigits:2｝））//->2 500,00兰特console.log（（2500）.toLocaleString（“en-GB”，｛style:“currency”，currency:“ZAR”，minimumFractionDigits:2｝））//->2500欧元
此答案符合以下标准：
不依赖于外部依赖项。支持本地化。有测试/证明。使用简单和最佳的编码实践（没有复杂的正则表达式，使用标准的编码模式）。
此代码基于其他答案中的概念。如果这是一个问题的话，它的执行速度应该是最好的。
var decimalCharacter = Number("1.1").toLocaleString().substr(1,1);
var defaultCurrencyMarker = "$";
function formatCurrency(number, currencyMarker) {
if (typeof number != "number")
number = parseFloat(number, 10);
// if NaN is passed in or comes from the parseFloat, set it to 0.
if (isNaN(number))
number = 0;
var sign = number < 0 ? "-" : "";
number = Math.abs(number); // so our signage goes before the $ symbol.
var integral = Math.floor(number);
var formattedIntegral = integral.toLocaleString();
// IE returns "##.00" while others return "##"
formattedIntegral = formattedIntegral.split(decimalCharacter)[0];
var decimal = Math.round((number - integral) * 100);
return sign + (currencyMarker || defaultCurrencyMarker) +
formattedIntegral +
decimalCharacter +
decimal.toString() + (decimal < 10 ? "0" : "");
}
这些测试仅适用于美国语言环境机器。做出这个决定是为了简单，因为这可能会导致糟糕的输入（错误的自动定位），从而导致糟糕的输出问题。
var tests = [
// [ input, expected result ]
[123123, "$123,123.00"], // no decimal
[123123.123, "$123,123.12"], // decimal rounded down
[123123.126, "$123,123.13"], // decimal rounded up
[123123.4, "$123,123.40"], // single decimal
["123123", "$123,123.00"], // repeat subset of the above using string input.
["123123.123", "$123,123.12"],
["123123.126", "$123,123.13"],
[-123, "-$123.00"] // negatives
];
for (var testIndex=0; testIndex < tests.length; testIndex++) {
var test = tests[testIndex];
var formatted = formatCurrency(test[0]);
if (formatted == test[1]) {
console.log("Test passed, \"" + test[0] + "\" resulted in \"" + formatted + "\"");
} else {
console.error("Test failed. Expected \"" + test[1] + "\", got \"" + formatted + "\"");
}
}
我喜欢简单：
function formatPriceUSD(price) {
var strPrice = price.toFixed(2).toString();
var a = strPrice.split('');
if (price > 1000000000)
a.splice(a.length - 12, 0, ',');
if (price > 1000000)
a.splice(a.length - 9, 0, ',');
if (price > 1000)
a.splice(a.length - 6, 0, ',');
return '$' + a.join("");
}
