格式化是通过格式操作使任意类型的数据转换成一个字符串。例如下面这样
<script>
console.log(chopper.format('{0} - {1} - {2}', 12, 24, 25)); // outputs "12 - 24 - 25"
</script>
下面是一个完整的代码，可以复制到自己的项目中。
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
</head>
<body>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script>
(function() {
var chopper = window.chopper = window.chopper || { cultures: {} },
math = Math,
formatRegExp = /\{(\d+)(:[^\}]+)?\}/g,
FUNCTION = "function",
STRING = "string",
NUMBER = "number",
OBJECT = "object",
NULL = "null",
BOOLEAN = "boolean",
UNDEFINED = "undefined",
slice = [].slice,
globalize = window.Globalize,
standardFormatRegExp = /^(n|c|p|e)(\d*)$/i,
literalRegExp = /(\\.)|(['][^']*[']?)|(["][^"]*["]?)/g,
commaRegExp = /\,/g,
EMPTY = "",
POINT = ".",
COMMA = ",",
SHARP = "#",
ZERO = "0",
PLACEHOLDER = "??",
EN = "en-US",
objectToString = {}.toString;
//cultures
chopper.cultures["en-US"] = {
name: EN,
numberFormat: {
pattern: ["-n"],
decimals: 2,
",": ",",
".": ".",
groupSize: [3],
percent: {
pattern: ["-n %", "n %"],
decimals: 2,
",": ",",
".": ".",
groupSize: [3],
symbol: "%"
},
currency: {
pattern: ["($n)", "$n"],
decimals: 2,
",": ",",
".": ".",
groupSize: [3],
symbol: "$"
}
},
calendars: {
standard: {
days: {
names: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
namesAbbr: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
namesShort: [ "Su", "Mo", "Tu", "We", "Th", "Fr", "Sa" ]
},
months: {
names: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
namesAbbr: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
},
AM: [ "AM", "am", "AM" ],
PM: [ "PM", "pm", "PM" ],
patterns: {
d: "M/d/yyyy",
D: "dddd, MMMM dd, yyyy",
F: "dddd, MMMM dd, yyyy h:mm:ss tt",
g: "M/d/yyyy h:mm tt",
G: "M/d/yyyy h:mm:ss tt",
m: "MMMM dd",
M: "MMMM dd",
s: "yyyy'-'MM'-'ddTHH':'mm':'ss",
t: "h:mm tt",
T: "h:mm:ss tt",
u: "yyyy'-'MM'-'dd HH':'mm':'ss'Z'",
y: "MMMM, yyyy",
Y: "MMMM, yyyy"
},
"/": "/",
":": ":",
firstDay: 0,
twoDigitYearMax: 2029
}
}
};
function findCulture(culture) {
if (culture) {
if (culture.numberFormat) {
return culture;
}
if (typeof culture === STRING) {
var cultures = chopper.cultures;
return cultures[culture] || cultures[culture.split("-")[0]] || null;
}
return null;
}
return null;
}
function getCulture(culture) {
if (culture) {
culture = findCulture(culture);
}
return culture || chopper.cultures.current;
}
function expandNumberFormat(numberFormat) {
numberFormat.groupSizes = numberFormat.groupSize;
numberFormat.percent.groupSizes = numberFormat.percent.groupSize;
numberFormat.currency.groupSizes = numberFormat.currency.groupSize;
}
chopper.culture = function(cultureName) {
var cultures = chopper.cultures, culture;
if (cultureName !== undefined) {
culture = findCulture(cultureName) || cultures[EN];
culture.calendar = culture.calendars.standard;
cultures.current = culture;
if (globalize && !globalize.load) {
expandNumberFormat(culture.numberFormat);
}
} else {
return cultures.current;
}
};
chopper.culture(EN);
//number formatting
function formatNumber(number, format, culture) {
culture = getCulture(culture);
var numberFormat = culture.numberFormat,
groupSize = numberFormat.groupSize[0],
groupSeparator = numberFormat[COMMA],
decimal = numberFormat[POINT],
precision = numberFormat.decimals,
pattern = numberFormat.pattern[0],
literals = [],
symbol,
isCurrency, isPercent,
customPrecision,
formatAndPrecision,
negative = number < 0,
integer,
fraction,
integerLength,
fractionLength,
replacement = EMPTY,
value = EMPTY,
idx,
length,
ch,
hasGroup,
hasNegativeFormat,
decimalIndex,
sharpIndex,
zeroIndex,
hasZero, hasSharp,
percentIndex,
currencyIndex,
startZeroIndex,
start = -1,
end;
//return empty string if no number
if (number === undefined) {
return EMPTY;
}
if (!isFinite(number)) {
return number;
}
//if no format then return number.toString() or number.toLocaleString() if culture.name is not defined
if (!format) {
return culture.name.length ? number.toLocaleString() : number.toString();
}
formatAndPrecision = standardFormatRegExp.exec(format);
// standard formatting
if (formatAndPrecision) {
format = formatAndPrecision[1].toLowerCase();
isCurrency = format === "c";
isPercent = format === "p";
if (isCurrency || isPercent) {
//get specific number format information if format is currency or percent
numberFormat = isCurrency ? numberFormat.currency : numberFormat.percent;
groupSize = numberFormat.groupSize[0];
groupSeparator = numberFormat[COMMA];
decimal = numberFormat[POINT];
precision = numberFormat.decimals;
symbol = numberFormat.symbol;
pattern = numberFormat.pattern[negative ? 0 : 1];
}
customPrecision = formatAndPrecision[2];
if (customPrecision) {
precision = +customPrecision;
}
//return number in exponential format
if (format === "e") {
return customPrecision ? number.toExponential(precision) : number.toExponential(); // toExponential() and toExponential(undefined) differ in FF #653438.
}
// multiply if format is percent
if (isPercent) {
number *= 100;
}
number = round(number, precision);
negative = number < 0;
number = number.split(POINT);
integer = number[0];
fraction = number[1];
//exclude "-" if number is negative.
if (negative) {
integer = integer.substring(1);
}
value = integer;
integerLength = integer.length;
//add group separator to the number if it is longer enough
if (integerLength >= groupSize) {
value = EMPTY;
for (idx = 0; idx < integerLength; idx++) {
if (idx > 0 && (integerLength - idx) % groupSize === 0) {
value += groupSeparator;
}
value += integer.charAt(idx);
}
}
if (fraction) {
value += decimal + fraction;
}
if (format === "n" && !negative) {
return value;
}
number = EMPTY;
for (idx = 0, length = pattern.length; idx < length; idx++) {
ch = pattern.charAt(idx);
if (ch === "n") {
number += value;
} else if (ch === "$" || ch === "%") {
number += symbol;
} else {
number += ch;
}
}
return number;
}
//custom formatting
//
//separate format by sections.
//make number positive
if (negative) {
number = -number;
}
if (format.indexOf("'") > -1 || format.indexOf("\"") > -1 || format.indexOf("\\") > -1) {
format = format.replace(literalRegExp, function (match) {
var quoteChar = match.charAt(0).replace("\\", ""),
literal = match.slice(1).replace(quoteChar, "");
literals.push(literal);
return PLACEHOLDER;
});
}
format = format.split(";");
if (negative && format[1]) {
//get negative format
format = format[1];
hasNegativeFormat = true;
} else if (number === 0) {
//format for zeros
format = format[2] || format[0];
if (format.indexOf(SHARP) == -1 && format.indexOf(ZERO) == -1) {
//return format if it is string constant.
return format;
}
} else {
format = format[0];
}
percentIndex = format.indexOf("%");
currencyIndex = format.indexOf("$");
isPercent = percentIndex != -1;
isCurrency = currencyIndex != -1;
//multiply number if the format has percent
if (isPercent) {
number *= 100;
}
if (isCurrency && format[currencyIndex - 1] === "\\") {
format = format.split("\\").join("");
isCurrency = false;
}
if (isCurrency || isPercent) {
//get specific number format information if format is currency or percent
numberFormat = isCurrency ? numberFormat.currency : numberFormat.percent;
groupSize = numberFormat.groupSize[0];
groupSeparator = numberFormat[COMMA];
decimal = numberFormat[POINT];
precision = numberFormat.decimals;
symbol = numberFormat.symbol;
}
hasGroup = format.indexOf(COMMA) > -1;
if (hasGroup) {
format = format.replace(commaRegExp, EMPTY);
}
decimalIndex = format.indexOf(POINT);
length = format.length;
if (decimalIndex != -1) {
fraction = number.toString().split("e");
if (fraction[1]) {
fraction = round(number, Math.abs(fraction[1]));
} else {
fraction = fraction[0];
}
fraction = fraction.split(POINT)[1] || EMPTY;
zeroIndex = format.lastIndexOf(ZERO) - decimalIndex;
sharpIndex = format.lastIndexOf(SHARP) - decimalIndex;
hasZero = zeroIndex > -1;
hasSharp = sharpIndex > -1;
idx = fraction.length;
if (!hasZero && !hasSharp) {
format = format.substring(0, decimalIndex) + format.substring(decimalIndex + 1);
length = format.length;
decimalIndex = -1;
idx = 0;
} if (hasZero && zeroIndex > sharpIndex) {
idx = zeroIndex;
} else if (sharpIndex > zeroIndex) {
if (hasSharp && idx > sharpIndex) {
idx = sharpIndex;
} else if (hasZero && idx < zeroIndex) {
idx = zeroIndex;
}
}
if (idx > -1) {
number = round(number, idx);
}
} else {
number = round(number);
}
sharpIndex = format.indexOf(SHARP);
startZeroIndex = zeroIndex = format.indexOf(ZERO);
//define the index of the first digit placeholder
if (sharpIndex == -1 && zeroIndex != -1) {
start = zeroIndex;
} else if (sharpIndex != -1 && zeroIndex == -1) {
start = sharpIndex;
} else {
start = sharpIndex > zeroIndex ? zeroIndex : sharpIndex;
}
sharpIndex = format.lastIndexOf(SHARP);
zeroIndex = format.lastIndexOf(ZERO);
//define the index of the last digit placeholder
if (sharpIndex == -1 && zeroIndex != -1) {
end = zeroIndex;
} else if (sharpIndex != -1 && zeroIndex == -1) {
end = sharpIndex;
} else {
end = sharpIndex > zeroIndex ? sharpIndex : zeroIndex;
}
if (start == length) {
end = start;
}
if (start != -1) {
value = number.toString().split(POINT);
integer = value[0];
fraction = value[1] || EMPTY;
integerLength = integer.length;
fractionLength = fraction.length;
if (negative && (number * -1) >= 0) {
negative = false;
}
//add group separator to the number if it is longer enough
if (hasGroup) {
if (integerLength === groupSize && integerLength < decimalIndex - startZeroIndex) {
integer = groupSeparator + integer;
} else if (integerLength > groupSize) {
value = EMPTY;
for (idx = 0; idx < integerLength; idx++) {
if (idx > 0 && (integerLength - idx) % groupSize === 0) {
value += groupSeparator;
}
value += integer.charAt(idx);
}
integer = value;
}
}
number = format.substring(0, start);
if (negative && !hasNegativeFormat) {
number += "-";
}
for (idx = start; idx < length; idx++) {
ch = format.charAt(idx);
if (decimalIndex == -1) {
if (end - idx < integerLength) {
number += integer;
break;
}
} else {
if (zeroIndex != -1 && zeroIndex < idx) {
replacement = EMPTY;
}
if ((decimalIndex - idx) <= integerLength && decimalIndex - idx > -1) {
number += integer;
idx = decimalIndex;
}
if (decimalIndex === idx) {
number += (fraction ? decimal : EMPTY) + fraction;
idx += end - decimalIndex + 1;
continue;
}
}
if (ch === ZERO) {
number += ch;
replacement = ch;
} else if (ch === SHARP) {
number += replacement;
}
}
if (end >= start) {
number += format.substring(end + 1);
}
//replace symbol placeholders
if (isCurrency || isPercent) {
value = EMPTY;
for (idx = 0, length = number.length; idx < length; idx++) {
ch = number.charAt(idx);
value += (ch === "$" || ch === "%") ? symbol : ch;
}
number = value;
}
length = literals.length;
if (length) {
for (idx = 0; idx < length; idx++) {
number = number.replace(PLACEHOLDER, literals[idx]);
}
}
}
return number;
}
var round = function(value, precision) {
precision = precision || 0;
value = value.toString().split('e');
value = Math.round(+(value[0] + 'e' + (value[1] ? (+value[1] + precision) : precision)));
value = value.toString().split('e');
value = +(value[0] + 'e' + (value[1] ? (+value[1] - precision) : -precision));
return value.toFixed(precision);
};
var toString = function(value, fmt, culture) {
if (fmt) {
if (typeof value === NUMBER) {
return formatNumber(value, fmt, culture);
}
}
return value !== undefined ? value : "";
};
if (globalize && !globalize.load) {
toString = function(value, format, culture) {
if ($.isPlainObject(culture)) {
culture = culture.name;
}
return globalize.format(value, format, culture);
};
}
chopper.format = function(fmt) {
var values = arguments;
return fmt.replace(formatRegExp, function(match, index, placeholderFormat) {
var value = values[parseInt(index, 10) + 1];
return toString(value, placeholderFormat ? placeholderFormat.substring(1) : "");
});
};
})();
</script>
</body>
</html>
API：
chopper.format('{0} is playing {1}', 'Xiaoming', 'basketball'); // outputs "Xiaoming is playing basketball"
// 价格
chopper.format('{0:c} - {1:c}', 10, 20); // outputs "10.00−20.00"
// 指数
chopper.format('指数: {0:e}', 25); // outputs "指数: 2.5e+1"
// 百分数
chopper.format('百分数: {0:p}', 25); // outputs "百分数: 2,500.00 %"
// 小数
chopper.format('小数: {0:n}', 25); // outputs "小数: 25.00"
小结：
开发中格式化数据还是经常用到的，比如我们要根据变量提示不同的信息，但是内容模板都是一样的，这样的话我们就可以使用此方法。如果你的项目使用jQuery，你也可以将上面的javascript封装成jQuery插件。