JavaScript等效于printf/String.Format

Question

我正在寻找一个很好的JavaScript等价的C/PHP printf()或C#/ Java程序员String.Format()(IFormatProvider对于.NET).

我的基本要求是现在有一千个数字分隔符格式,但处理许多组合(包括日期)的东西会很好.

我意识到Microsoft的Ajax库提供了一个版本String.Format(),但我们不希望该框架的整个开销.

Answer 1

基于之前建议的解决方案:

// First, checks if it isn't implemented yet.
if (!String.prototype.format) {
  String.prototype.format = function() {
    var args = arguments;
    return this.replace(/{(\d+)}/g, function(match, number) { 
      return typeof args[number] != 'undefined'
        ? args[number]
        : match
      ;
    });
  };
}

"{0} is dead, but {1} is alive! {0} {2}".format("ASP", "ASP.NET")

输出

ASP已经死了,但ASP.NET还活着!ASP {2}

如果你不想修改String原型:

if (!String.format) {
  String.format = function(format) {
    var args = Array.prototype.slice.call(arguments, 1);
    return format.replace(/{(\d+)}/g, function(match, number) { 
      return typeof args[number] != 'undefined'
        ? args[number] 
        : match
      ;
    });
  };
}

给你更熟悉的东西:

String.format('{0} is dead, but {1} is alive! {0} {2}', 'ASP', 'ASP.NET');

结果相同:

ASP已经死了,但ASP.NET还活着!ASP {2}

Answer 2

从ES6开始,您可以使用模板字符串:

let soMany = 10;
console.log(`This is ${soMany} times easier!`);
// "This is 10 times easier!

有关详细信息,请参阅下面的Kim的答案.

除此以外:

试试用于JavaScript的sprintf().

如果你真的想自己做一个简单的格式化方法,不要连续进行替换,而是同时进行.

因为当前替换的替换字符串也包含如下格式序列时,提及的大多数其他提议都会失败:

"{0}{1}".format("{1}", "{0}")

通常你会期望输出是,{1}{0}但实际输出是{1}{1}.所以同时替换就像在恐惧症的建议中一样.

Answer 3

这很有趣,因为Stack Overflow实际上有一个String叫做原型的格式化函数formatUnicorn.试试吧!进入控制台并键入以下内容:

"Hello, {name}, are you feeling {adjective}?".formatUnicorn({name:"Gabriel", adjective: "OK"});

你得到这个输出:

Hello, Gabriel, are you feeling OK?

您可以使用对象,数组和字符串作为参数!我得到了它的代码并重新编写它以生成一个新版本String.prototype.format:

String.prototype.formatUnicorn = String.prototype.formatUnicorn ||
function () {
    "use strict";
    var str = this.toString();
    if (arguments.length) {
        var t = typeof arguments[0];
        var key;
        var args = ("string" === t || "number" === t) ?
            Array.prototype.slice.call(arguments)
            : arguments[0];

        for (key in args) {
            str = str.replace(new RegExp("\\{" + key + "\\}", "gi"), args[key]);
        }
    }

    return str;
};

注意聪明的Array.prototype.slice.call(arguments)调用 - 这意味着如果你抛出的是字符串或数字的参数,而不是单个JSON样式的对象,你String.Format几乎可以完全获得C#的行为.

"a{0}bcd{1}ef".formatUnicorn("foo", "bar"); // yields "aFOObcdBARef"

那是因为Array's slice将强制arguments进入一个Array,无论它是否是原来的,并且key将是每个数组元素的索引(0,1,2 ......)强制成一个字符串(例如,"0",所以"\\{0\\}"为你的第一个正则表达式模式).

整齐.

Answer 4

JavaScript中的数字格式

我到了这个问题页面,希望找到如何在JavaScript中格式化数字,而不引入另一个库.这是我发现的:

舍入浮点数

sprintf("%.2f", num)似乎是JavaScript中的等效num.toFixed(2)格式,格式化num为2位小数,带有舍入(但请参阅@ ars265关于Math.round下面的注释).

(12.345).toFixed(2); // returns "12.35" (rounding!)
(12.3).toFixed(2); // returns "12.30" (zero padding)

指数形式

相当于sprintf("%.2e", num)是num.toExponential(2).

(33333).toExponential(2); // "3.33e+4"

十六进制和其他基础

要在基数B中打印数字,请尝试num.toString(B).JavaScript支持自动转换到基数2到36(此外,某些浏览器对base64编码的支持有限).

(3735928559).toString(16); // to base 16: "deadbeef"
parseInt("deadbeef", 16); // from base 16: 3735928559

参考页面

关于JS数字格式的快速教程

toFixed()的Mozilla参考页面(带有指向toPrecision(),toExponential(),toLocaleString(),...的链接)

Answer 5

从ES6开始,您可以使用模板字符串:

let soMany = 10;
console.log(`This is ${soMany} times easier!`);
// "This is 10 times easier!

请注意,模板字符串被反引号 `而不是(单个)引号包围.

了解更多信息:

https://developers.google.com/web/updates/2015/01/ES6-Template-Strings

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/template_strings

注意:检查mozilla-site以查找支持的浏览器列表.

Answer 6

jsxt,Zippo

此选项更适合.

String.prototype.format = function() {
    var formatted = this;
    for (var i = 0; i < arguments.length; i++) {
        var regexp = new RegExp('\\{'+i+'\\}', 'gi');
        formatted = formatted.replace(regexp, arguments[i]);
    }
    return formatted;
};

使用此选项,我可以替换这些字符串:

'The {0} is dead. Don\'t code {0}. Code {1} that is open source!'.format('ASP', 'PHP');

使用您的代码,第二个{0}将不会被替换.;)

Answer 7

我用这个简单的功能:

String.prototype.format = function() {
    var formatted = this;
    for( var arg in arguments ) {
        formatted = formatted.replace("{" + arg + "}", arguments[arg]);
    }
    return formatted;
};

这与string.format非常相似:

"{0} is dead, but {1} is alive!".format("ASP", "ASP.NET")

Answer 8

对于Node.js用户,util.format它具有类似printf的功能:

util.format("%s world", "Hello")

Answer 9

我很惊讶没有人使用过reduce,这是一个原生简洁而强大的JavaScript功能.

ES6(EcmaScript2015)

String.prototype.format = function() {
  return [...arguments].reduce((p,c) => p.replace(/%s/,c), this);
};

console.log('Is that a %s or a %s?... No, it\'s %s!'.format('plane', 'bird', 'SOman'));

<ES6

function interpolate(theString, argumentArray) {
    var regex = /%s/;
    var _r=function(p,c){return p.replace(regex,c);}
    return argumentArray.reduce(_r, theString);
}

interpolate("%s, %s and %s", ["Me", "myself", "I"]); // "Me, myself and I"

这个怎么运作:

reduce对累加器和数组中的每个元素(从左到右)应用函数以将其减少为单个值.

var _r= function(p,c){return p.replace(/%s/,c)};

console.log(
  ["a", "b", "c"].reduce(_r, "[%s], [%s] and [%s]") + '\n',
  [1, 2, 3].reduce(_r, "%s+%s=%s") + '\n',
  ["cool", 1337, "stuff"].reduce(_r, "%s %s %s")
);

Answer 10

这是JavaScript中sprintf 的最小实现:它只执行"%s"和"%d",但是我留下了空间来扩展它.它对OP来说毫无用处,但其他偶然发现来自谷歌的人可能会从中受益.

function sprintf() {
    var args = arguments,
    string = args[0],
    i = 1;
    return string.replace(/%((%)|s|d)/g, function (m) {
        // m is the matched format, e.g. %s, %d
        var val = null;
        if (m[2]) {
            val = m[2];
        } else {
            val = args[i];
            // A switch statement so that the formatter can be extended. Default is %s
            switch (m) {
                case '%d':
                    val = parseFloat(val);
                    if (isNaN(val)) {
                        val = 0;
                    }
                    break;
            }
            i++;
        }
        return val;
    });
}

例:

alert(sprintf('Latitude: %s, Longitude: %s, Count: %d', 41.847, -87.661, 'two'));
// Expected output: Latitude: 41.847, Longitude: -87.661, Count: 0

与以往的答复类似的解决方案对比,这其中做了所有替代一气呵成,所以它不会取代先前所取代值的部分.

Answer 11

格式化 JavaScript 字符串的 3 种不同方法

有 3 种不同的方法可以通过用变量值替换占位符来格式化字符串。

1. 使用模板文字（反引号``）

   let name = 'John';
   let age = 30;
   // using backticks
   console.log(`${name} is ${age} years old.`);
   // John is 30 years old.

2. 使用串联

let name = 'John';
let age = 30;
// using concatenation
console.log(name + ' is ' + age + ' years old.');
// John is 30 years old.

3. 创建自己的格式函数

String.prototype.format = function () {
  var args = arguments;
  return this.replace(/{([0-9]+)}/g, function (match, index) {
    // check if the argument is there
    return typeof args[index] == 'undefined' ? match : args[index];
  });
};


console.log('{0} is {1} years old.'.format('John', 30));

Answer 12

JavaScript程序员可以在https://github.com/ildar-shaimordanov/jsxt/blob/master/js/String.js上使用String.prototype.sprintf .以下是示例:

var d = new Date();
var dateStr = '%02d:%02d:%02d'.sprintf(
    d.getHours(), 
    d.getMinutes(), 
    d.getSeconds());

Answer 13

添加到zippoxer答案,我使用此功能:

String.prototype.format = function () {
    var a = this, b;
    for (b in arguments) {
        a = a.replace(/%[a-z]/, arguments[b]);
    }
    return a; // Make chainable
};

var s = 'Hello %s The magic number is %d.';
s.format('world!', 12); // Hello World! The magic number is 12.

我还有一个非原型版本,我经常使用它的类似Java的语法:

function format() {
    var a, b, c;
    a = arguments[0];
    b = [];
    for(c = 1; c < arguments.length; c++){
        b.push(arguments[c]);
    }
    for (c in b) {
        a = a.replace(/%[a-z]/, b[c]);
    }
    return a;
}
format('%d ducks, 55 %s', 12, 'cats'); // 12 ducks, 55 cats

ES 2015更新

ES 2015中所有酷炫的新东西都让这更容易:

function format(fmt, ...args){
    return fmt
        .split("%%")
        .reduce((aggregate, chunk, i) =>
            aggregate + chunk + (args[i] || ""), "");
}

format("Hello %%! I ate %% apples today.", "World", 44);
// "Hello World, I ate 44 apples today."

我认为,因为这与旧版本一样,实际上并不解析字母,所以也可以只使用一个令牌%%.这具有显而易见的优点,并且不会使单个使用变得困难%.但是,如果%%由于某种原因需要,则需要将其替换为自身:

format("I love percentage signs! %%", "%%");
// "I love percentage signs! %%"

Answer 14

+1 Zippo除了函数体需要如下所示,否则它会在每次迭代时附加当前字符串:

String.prototype.format = function() {
    var formatted = this;
    for (var arg in arguments) {
        formatted = formatted.replace("{" + arg + "}", arguments[arg]);
    }
    return formatted;
};

Answer 15

我想分享我对'问题'的解决方案.我没有重新发明轮子,但试图找到一个基于JavaScript已经做的解决方案.优点是,您可以免费获得所有隐式转换.设置String的prototype属性$提供了非常好的紧凑语法(参见下面的示例).它可能不是最有效的方式,但在大多数情况下处理输出它不必超级优化.

String.form = function(str, arr) {
    var i = -1;
    function callback(exp, p0, p1, p2, p3, p4) {
        if (exp=='%%') return '%';
        if (arr[++i]===undefined) return undefined;
        exp  = p2 ? parseInt(p2.substr(1)) : undefined;
        var base = p3 ? parseInt(p3.substr(1)) : undefined;
        var val;
        switch (p4) {
            case 's': val = arr[i]; break;
            case 'c': val = arr[i][0]; break;
            case 'f': val = parseFloat(arr[i]).toFixed(exp); break;
            case 'p': val = parseFloat(arr[i]).toPrecision(exp); break;
            case 'e': val = parseFloat(arr[i]).toExponential(exp); break;
            case 'x': val = parseInt(arr[i]).toString(base?base:16); break;
            case 'd': val = parseFloat(parseInt(arr[i], base?base:10).toPrecision(exp)).toFixed(0); break;
        }
        val = typeof(val)=='object' ? JSON.stringify(val) : val.toString(base);
        var sz = parseInt(p1); /* padding size */
        var ch = p1 && p1[0]=='0' ? '0' : ' '; /* isnull? */
        while (val.length<sz) val = p0 !== undefined ? val+ch : ch+val; /* isminus? */
       return val;
    }
    var regex = /%(-)?(0?[0-9]+)?([.][0-9]+)?([#][0-9]+)?([scfpexd%])/g;
    return str.replace(regex, callback);
}

String.prototype.$ = function() {
    return String.form(this, Array.prototype.slice.call(arguments));
}

这里有一些例子:

String.format("%s %s", [ "This is a string", 11 ])
console.log("%s %s".$("This is a string", 11))
var arr = [ "12.3", 13.6 ]; console.log("Array: %s".$(arr));
var obj = { test:"test", id:12 }; console.log("Object: %s".$(obj));
console.log("%c", "Test");
console.log("%5d".$(12)); // '   12'
console.log("%05d".$(12)); // '00012'
console.log("%-5d".$(12)); // '12   '
console.log("%5.2d".$(123)); // '  120'
console.log("%5.2f".$(1.1)); // ' 1.10'
console.log("%10.2e".$(1.1)); // '   1.10e+0'
console.log("%5.3p".$(1.12345)); // ' 1.12'
console.log("%5x".$(45054)); // ' affe'
console.log("%20#2x".$("45054")); // '    1010111111111110'
console.log("%6#2d".$("111")); // '     7'
console.log("%6#16d".$("affe")); // ' 45054'

Answer 16

我会添加自己的发现,因为我问过:

• number_format(用于千位分隔符/货币格式)
• sprintf(与上面的作者相同)

可悲的是,似乎sprintf没有像.NET的字符串格式那样处理千位分隔符格式.

Answer 17

我使用一个名为String.format for JavaScript的小库,它支持大多数格式字符串功能(包括数字和日期的格式),并使用.NET语法.脚本本身小于4 kB,因此不会产生太多开销.

Answer 18

十分优雅:

String.prototype.format = function (){
    var args = arguments;
    return this.replace(/\{\{|\}\}|\{(\d+)\}/g, function (curlyBrack, index) {
        return ((curlyBrack == "{{") ? "{" : ((curlyBrack == "}}") ? "}" : args[index]));
    });
};

// Usage:
"{0}{1}".format("{1}", "{0}")

信用去 (断链) https://gist.github.com/0i0/1519811

Answer 19

如果您要处理千位分隔符,您应该使用JavaScript Number类中的toLocaleString(),因为它将格式化用户区域的字符串.

JavaScript Date类可以格式化本地化的日期和时间.

Answer 20

我用这个:

String.prototype.format = function() {
    var newStr = this, i = 0;
    while (/%s/.test(newStr))
        newStr = newStr.replace("%s", arguments[i++])

    return newStr;
}

然后我称之为:

"<h1>%s</h1><p>%s</p>".format("Header", "Just a test!");

Answer 21

我有一个非常接近彼得的解决方案,但它涉及数字和对象的情况.

if (!String.prototype.format) {
  String.prototype.format = function() {
    var args;
    args = arguments;
    if (args.length === 1 && args[0] !== null && typeof args[0] === 'object') {
      args = args[0];
    }
    return this.replace(/{([^}]*)}/g, function(match, key) {
      return (typeof args[key] !== "undefined" ? args[key] : match);
    });
  };
}

也许处理所有深层次的情况可能更好,但是对于我的需求,这很好.

"This is an example from {name}".format({name:"Blaine"});
"This is an example from {0}".format("Blaine");

PS:如果您在AngularJS等模板框架中使用翻译,这个功能非常酷:

<h1> {{('hello-message'|translate).format(user)}} <h1>
<h1> {{('hello-by-name'|translate).format( user ? user.name : 'You' )}} <h1>

en.json就像

{
    "hello-message": "Hello {name}, welcome.",
    "hello-by-name": "Hello {0}, welcome."
}

Answer 22

该PHPJS项目写JavaScript实现的许多PHP的功能.由于PHP的sprintf()功能与C基本相同printf(),因此它们的JavaScript实现应满足您的需求.

Answer 23

一个非常不同的版本,我喜欢的版本(这个版本使用{xxx}令牌而不是{0}编号的参数,这更加自我记录并且更适合本地化):

String.prototype.format = function(tokens) {
  var formatted = this;
  for (var token in tokens)
    if (tokens.hasOwnProperty(token))
      formatted = formatted.replace(RegExp("{" + token + "}", "g"), tokens[token]);
  return formatted;
};

变化将是:

  var formatted = l(this);

首先调用l()本地化函数.

Answer 24

您可以在http://www.webtoolkit.info/javascript-sprintf.html找到JavaScript的"sprintf" .

Answer 25

对于那些喜欢Node.JS及其util.format功能的人,我只是把它解压缩到它的vanilla JavaScript表单中(只有util.format使用的函数):

exports = {};

function isString(arg) {
    return typeof arg === 'string';
}
function isNull(arg) {
    return arg === null;
}
function isObject(arg) {
    return typeof arg === 'object' && arg !== null;
}
function isBoolean(arg) {
    return typeof arg === 'boolean';
}
function isUndefined(arg) {
    return arg === void 0;
}
function stylizeNoColor(str, styleType) {
    return str;
}
function stylizeWithColor(str, styleType) {
    var style = inspect.styles[styleType];

    if (style) {
        return '\u001b[' + inspect.colors[style][0] + 'm' + str +
            '\u001b[' + inspect.colors[style][3] + 'm';
    } else {
        return str;
    }
}
function isFunction(arg) {
    return typeof arg === 'function';
}
function isNumber(arg) {
    return typeof arg === 'number';
}
function isSymbol(arg) {
    return typeof arg === 'symbol';
}
function formatPrimitive(ctx, value) {
    if (isUndefined(value))
        return ctx.stylize('undefined', 'undefined');
    if (isString(value)) {
        var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                .replace(/'/g, "\\'")
                .replace(/\\"/g, '"') + '\'';
        return ctx.stylize(simple, 'string');
    }
    if (isNumber(value)) {
        // Format -0 as '-0'. Strict equality won't distinguish 0 from -0,
        // so instead we use the fact that 1 / -0 < 0 whereas 1 / 0 > 0 .
        if (value === 0 && 1 / value < 0)
            return ctx.stylize('-0', 'number');
        return ctx.stylize('' + value, 'number');
    }
    if (isBoolean(value))
        return ctx.stylize('' + value, 'boolean');
    // For some reason typeof null is "object", so special case here.
    if (isNull(value))
        return ctx.stylize('null', 'null');
    // es6 symbol primitive
    if (isSymbol(value))
        return ctx.stylize(value.toString(), 'symbol');
}
function arrayToHash(array) {
    var hash = {};

    array.forEach(function (val, idx) {
        hash[val] = true;
    });

    return hash;
}
function objectToString(o) {
    return Object.prototype.toString.call(o);
}
function isDate(d) {
    return isObject(d) && objectToString(d) === '[object Date]';
}
function isError(e) {
    return isObject(e) &&
        (objectToString(e) === '[object Error]' || e instanceof Error);
}
function isRegExp(re) {
    return isObject(re) && objectToString(re) === '[object RegExp]';
}
function formatError(value) {
    return '[' + Error.prototype.toString.call(value) + ']';
}
function formatPrimitiveNoColor(ctx, value) {
    var stylize = ctx.stylize;
    ctx.stylize = stylizeNoColor;
    var str = formatPrimitive(ctx, value);
    ctx.stylize = stylize;
    return str;
}
function isArray(ar) {
    return Array.isArray(ar);
}
function hasOwnProperty(obj, prop) {
    return Object.prototype.hasOwnProperty.call(obj, prop);
}
function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
    var name, str, desc;
    desc = Object.getOwnPropertyDescriptor(value, key) || {value: value[key]};
    if (desc.get) {
        if (desc.set) {
            str = ctx.stylize('[Getter/Setter]', 'special');
        } else {
            str = ctx.stylize('[Getter]', 'special');
        }
    } else {
        if (desc.set) {
            str = ctx.stylize('[Setter]', 'special');
        }
    }
    if (!hasOwnProperty(visibleKeys, key)) {
        name = '[' + key + ']';
    }
    if (!str) {
        if (ctx.seen.indexOf(desc.value) < 0) {
            if (isNull(recurseTimes)) {
                str = formatValue(ctx, desc.value, null);
            } else {
                str = formatValue(ctx, desc.value, recurseTimes - 1);
            }
            if (str.indexOf('\n') > -1) {
                if (array) {
                    str = str.split('\n').map(function (line) {
                        return '  ' + line;
                    }).join('\n').substr(2);
                } else {
                    str = '\n' + str.split('\n').map(function (line) {
                        return '   ' + line;
                    }).join('\n');
                }
            }
        } else {
            str = ctx.stylize('[Circular]', 'special');
        }
    }
    if (isUndefined(name)) {
        if (array && key.match(/^\d+$/)) {
            return str;
        }
        name = JSON.stringify('' + key);
        if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
            name = name.substr(1, name.length - 2);
            name = ctx.stylize(name, 'name');
        } else {
            name = name.replace(/'/g, "\\'")
                .replace(/\\"/g, '"')
                .replace(/(^"|"$)/g, "'")
                .replace(/\\\\/g, '\\');
            name = ctx.stylize(name, 'string');
        }
    }

    return name + ': ' + str;
}
function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
    var output = [];
    for (var i = 0, l = value.length; i < l; ++i) {
        if (hasOwnProperty(value, String(i))) {
            output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
                String(i), true));
        } else {
            output.push('');
        }
    }
    keys.forEach(function (key) {
        if (!key.match(/^\d+$/)) {
            output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
                key, true));
        }
    });
    return output;
}
function reduceToSingleString(output, base, braces) {
    var length = output.reduce(function (prev, cur) {
        return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
    }, 0);

    if (length > 60) {
        return braces[0] +
            (base === '' ? '' : base + '\n ') +
            ' ' +
            output.join(',\n  ') +
            ' ' +
            braces[1];
    }

    return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}
function formatValue(ctx, value, recurseTimes) {
    // Provide a hook for user-specified inspect functions.
    // Check that value is an object with an inspect function on it
    if (ctx.customInspect &&
        value &&
        isFunction(value.inspect) &&
            // Filter out the util module, it's inspect function is special
        value.inspect !== exports.inspect &&
            // Also filter out any prototype objects using the circular check.
        !(value.constructor && value.constructor.prototype === value)) {
        var ret = value.inspect(recurseTimes, ctx);
        if (!isString(ret)) {
            ret = formatValue(ctx, ret, recurseTimes);
        }
        return ret;
    }

    // Primitive types cannot have properties
    var primitive = formatPrimitive(ctx, value);
    if (primitive) {
        return primitive;
    }

    // Look up the keys of the object.
    var keys = Object.keys(value);
    var visibleKeys = arrayToHash(keys);

    if (ctx.showHidden) {
        keys = Object.getOwnPropertyNames(value);
    }

    // This could be a boxed primitive (new String(), etc.), check valueOf()
    // NOTE: Avoid calling `valueOf` on `Date` instance because it will return
    // a number which, when object has some additional user-stored `keys`,
    // will be printed out.
    var formatted;
    var raw = value;
    try {
        // the .valueOf() call can fail for a multitude of reasons
        if (!isDate(value))
            raw = value.valueOf();
    } catch (e) {
        // ignore...
    }

    if (isString(raw)) {
        // for boxed Strings, we have to remove the 0-n indexed entries,
        // since they just noisey up the output and are redundant
        keys = keys.filter(function (key) {
            return !(key >= 0 && key < raw.length);
        });
    }

    // Some type of object without properties can be shortcutted.
    if (keys.length === 0) {
        if (isFunction(value)) {
            var name = value.name ? ': ' + value.name : '';
            return ctx.stylize('[Function' + name + ']', 'special');
        }
        if (isRegExp(value)) {
            return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
        }
        if (isDate(value)) {
            return ctx.stylize(Date.prototype.toString.call(value), 'date');
        }
        if (isError(value)) {
            return formatError(value);
        }
        // now check the `raw` value to handle boxed primitives
        if (isString(raw)) {
            formatted = formatPrimitiveNoColor(ctx, raw);
            return ctx.stylize('[String: ' + formatted + ']', 'string');
        }
        if (isNumber(raw)) {
            formatted = formatPrimitiveNoColor(ctx, raw);
            return ctx.stylize('[Number: ' + formatted + ']', 'number');
        }
        if (isBoolean(raw)) {
            formatted = formatPrimitiveNoColor(ctx, raw);
            return ctx.stylize('[Boolean: ' + formatted + ']', 'boolean');
        }
    }

    var base = '', array = false, braces = ['{', '}'];

    // Make Array say that they are Array
    if (isArray(value)) {
        array = true;
        braces = ['[', ']'];
    }

    // Make functions say that they are functions
    if (isFunction(value)) {
        var n = value.name ? ': ' + value.name : '';
        base = ' [Function' + n + ']';
    }

    // Make RegExps say that they are RegExps
    if (isRegExp(value)) {
        base = ' ' + RegExp.prototype.toString.call(value);
    }

    // Make dates with properties first say the date
    if (isDate(value)) {
        base = ' ' + Date.prototype.toUTCString.call(value);
    }

    // Make error with message first say the error
    if (isError(value)) {
        base = ' ' + formatError(value);
    }

    // Make boxed primitive Strings look like such
    if (isString(raw)) {
        formatted = formatPrimitiveNoColor(ctx, raw);
        base = ' ' + '[String: ' + formatted + ']';
    }

    // Make boxed primitive Numbers look like such
    if (isNumber(raw)) {
        formatted = formatPrimitiveNoColor(ctx, raw);
        base = ' ' + '[Number: ' + formatted + ']';
    }

    // Make boxed primitive Booleans look like such
    if (isBoolean(raw)) {
        formatted = formatPrimitiveNoColor(ctx, raw);
        base = ' ' + '[Boolean: ' + formatted + ']';
    }

    if (keys.length === 0 && (!array || value.length === 0)) {
        return braces[0] + base + braces[1];
    }

    if (recurseTimes < 0) {
        if (isRegExp(value)) {
            return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
        } else {
            return ctx.stylize('[Object]', 'special');
        }
    }

    ctx.seen.push(value);

    var output;
    if (array) {
        output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
    } else {
        output = keys.map(function (key) {
            return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
        });
    }

    ctx.seen.pop();

    return reduceToSingleString(output, base, braces);
}
function inspect(obj, opts) {
    // default options
    var ctx = {
        seen: [],
        stylize: stylizeNoColor
    };
    // legacy...
    if (arguments.length >= 3) ctx.depth = arguments[2];
    if (arguments.length >= 4) ctx.colors = arguments[3];
    if (isBoolean(opts)) {
        // legacy...
        ctx.showHidden = opts;
    } else if (opts) {
        // got an "options" object
        exports._extend(ctx, opts);
    }
    // set default options
    if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
    if (isUndefined(ctx.depth)) ctx.depth = 2;
    if (isUndefined(ctx.colors)) ctx.colors = false;
    if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
    if (ctx.colors) ctx.stylize = stylizeWithColor;
    return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
    'bold': [1, 22],
    'italic': [3, 23],
    'underline': [4, 24],
    'inverse': [7, 27],
    'white': [37, 39],
    'grey': [90, 39],
    'black': [30, 39],
    'blue': [34, 39],
    'cyan': [36, 39],
    'green': [32, 39],
    'magenta': [35, 39],
    'red': [31, 39],
    'yellow': [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
    'special': 'cyan',
    'number': 'yellow',
    'boolean': 'yellow',
    'undefined': 'grey',
    'null': 'bold',
    'string': 'green',
    'symbol': 'green',
    'date': 'magenta',
    // "name": intentionally not styling
    'regexp': 'red'
};


var formatRegExp = /%[sdj%]/g;
exports.format = function (f) {
    if (!isString(f)) {
        var objects = [];
        for (var j = 0; j < arguments.length; j++) {
            objects.push(inspect(arguments[j]));
        }
        return objects.join(' ');
    }

    var i = 1;
    var args = arguments;
    var len = args.length;
    var str = String(f).replace(formatRegExp, function (x) {
        if (x === '%%') return '%';
        if (i >= len) return x;
        switch (x) {
            case '%s':
                return String(args[i++]);
            case '%d':
                return Number(args[i++]);
            case '%j':
                try {
                    return JSON.stringify(args[i++]);
                } catch (_) {
                    return '[Circular]';
                }
            default:
                return x;
        }
    });
    for (var x = args[i]; i < len; x = args[++i]) {
        if (isNull(x) || !isObject(x)) {
            str += ' ' + x;
        } else {
            str += ' ' + inspect(x);
        }
    }
    return str;
};

收获自:https://github.com/joyent/node/blob/master/lib/util.js

Answer 26

对于基本格式:

var template = jQuery.validator.format("{0} is not a valid value");
var result = template("abc");

Answer 27

我在这里有一个稍长的JavaScript格式化程序...

你可以用几种方式格式化:

• String.format(input, args0, arg1, ...)
• String.format(input, obj)
• "literal".format(arg0, arg1, ...)
• "literal".format(obj)

此外,如果您说ObjectBase.prototype.format(例如使用DateJS),它将使用它.

例子...

var input = "numbered args ({0}-{1}-{2}-{3})";
console.log(String.format(input, "first", 2, new Date()));
//Outputs "numbered args (first-2-Thu May 31 2012...Time)-{3})"

console.log(input.format("first", 2, new Date()));
//Outputs "numbered args(first-2-Thu May 31 2012...Time)-{3})"

console.log(input.format(
    "object properties ({first}-{second}-{third:yyyy-MM-dd}-{fourth})"
    ,{
        'first':'first'
        ,'second':2
        ,'third':new Date() //assumes Date.prototype.format method
    }
));
//Outputs "object properties (first-2-2012-05-31-{3})"

我也使用.asFormat别名并且已经有一些检测,以防已经有一个string.format(例如使用MS Ajax Toolkit(我讨厌那个库).

Answer 28

万一有人需要一个防止污染全局范围的函数，下面的函数也可以这样做：

  function _format (str, arr) {
    return str.replace(/{(\d+)}/g, function (match, number) {
      return typeof arr[number] != 'undefined' ? arr[number] : match;
    });
  };

Answer 29

使用Lodash你可以获得模板功能：

使用 ES 模板文字分隔符作为“插值”分隔符。通过替换“插值”分隔符来禁用支持。

var compiled = _.template('hello ${ user }!');
compiled({ 'user': 'pebbles' });
// => 'hello pebbles!

Answer 30

我们可以为 Typescript使用一个简单的轻量级String.Format字符串操作库。

字符串格式（）：

var id = image.GetId()
String.Format("image_{0}.jpg", id)
output: "image_2db5da20-1c5d-4f1a-8fd4-b41e34c8c5b5.jpg";

说明符的字符串格式：

var value = String.Format("{0:L}", "APPLE"); //output "apple"

value = String.Format("{0:U}", "apple"); // output "APPLE"

value = String.Format("{0:d}", "2017-01-23 00:00"); //output "23.01.2017"


value = String.Format("{0:s}", "21.03.2017 22:15:01") //output "2017-03-21T22:15:01"

value = String.Format("{0:n}", 1000000);
//output "1.000.000"

value = String.Format("{0:00}", 1);
//output "01"

对象的字符串格式，包括说明符：

var fruit = new Fruit();
fruit.type = "apple";
fruit.color = "RED";
fruit.shippingDate = new Date(2018, 1, 1);
fruit.amount = 10000;

String.Format("the {type:U} is {color:L} shipped on {shippingDate:s} with an amount of {amount:n}", fruit);
// output: the APPLE is red shipped on 2018-01-01 with an amount of 10.000