哇，已经有这么多答案了。我很确定这件事会被埋葬。即便如此，我觉得这对一些人来说可能有用。

我对所选的答案并不完全满意，因为在ES6中，默认值不能很好地工作。它也不提供默认值信息。我还想要一个不依赖于外部库的轻量级函数。

这个函数对于调试非常有用，例如:记录被调用函数的参数、默认参数值和参数。

我昨天花了一些时间在这个问题上，破解正确的RegExp来解决这个问题，这就是我想到的。它运行得非常好，我对结果非常满意:

const REGEX_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg; const REGEX_FUNCTION_PARAMS = /(?:\s*(?:function\s*[^(]*)?\s*)((?:[^'"]|(?:(?:(['"])(?:(?:.*?[^\\]\2)|\2))))*?)\s*(?=(?:=>)|{)/m const REGEX_PARAMETERS_VALUES = /\s*(\w+)\s*(?:=\s*((?:(?:(['"])(?:\3|(?:.*?[^\\]\3)))((\s*\+\s*)(?:(?:(['"])(?:\6|(?:.*?[^\\]\6)))|(?:[\w$]*)))*)|.*?))?\s*(?:,|$)/gm /** * Retrieve a function's parameter names and default values * Notes: * - parameters with default values will not show up in transpiler code (Babel) because the parameter is removed from the function. * - does NOT support inline arrow functions as default values * to clarify: ( name = "string", add = defaultAddFunction ) - is ok * ( name = "string", add = ( a )=> a + 1 ) - is NOT ok * - does NOT support default string value that are appended with a non-standard ( word characters or $ ) variable name * to clarify: ( name = "string" + b ) - is ok * ( name = "string" + $b ) - is ok * ( name = "string" + b + "!" ) - is ok * ( name = "string" + λ ) - is NOT ok * @param {function} func * @returns {Array} - An array of the given function's parameter [key, default value] pairs. */ function getParams(func) { let functionAsString = func.toString() let params = [] let match functionAsString = functionAsString.replace(REGEX_COMMENTS, '') functionAsString = functionAsString.match(REGEX_FUNCTION_PARAMS)[1] if (functionAsString.charAt(0) === '(') functionAsString = functionAsString.slice(1, -1) while (match = REGEX_PARAMETERS_VALUES.exec(functionAsString)) params.push([match[1], match[2]]) return params } // Lets run some tests! var defaultName = 'some name' function test1(param1, param2, param3) { return (param1) => param1 + param2 + param3 } function test2(param1, param2 = 4 * (5 / 3), param3) {} function test3(param1, param2 = "/root/" + defaultName + ".jpeg", param3) {} function test4(param1, param2 = (a) => a + 1) {} console.log(getParams(test1)) console.log(getParams(test2)) console.log(getParams(test3)) console.log(getParams(test4)) // [ [ 'param1', undefined ], [ 'param2', undefined ], [ 'param3', undefined ] ] // [ [ 'param1', undefined ], [ 'param2', '4 * (5 / 3)' ], [ 'param3', undefined ] ] // [ [ 'param1', undefined ], [ 'param2', '"/root/" + defaultName + ".jpeg"' ], [ 'param3', undefined ] ] // [ [ 'param1', undefined ], [ 'param2', '( a' ] ] // --> This last one fails because of the inlined arrow function! var arrowTest1 = (a = 1) => a + 4 var arrowTest2 = a => b => a + b var arrowTest3 = (param1 = "/" + defaultName) => { return param1 + '...' } var arrowTest4 = (param1 = "/" + defaultName, param2 = 4, param3 = null) => { () => param3 ? param3 : param2 } console.log(getParams(arrowTest1)) console.log(getParams(arrowTest2)) console.log(getParams(arrowTest3)) console.log(getParams(arrowTest4)) // [ [ 'a', '1' ] ] // [ [ 'a', undefined ] ] // [ [ 'param1', '"/" + defaultName' ] ] // [ [ 'param1', '"/" + defaultName' ], [ 'param2', '4' ], [ 'param3', 'null' ] ] console.log(getParams((param1) => param1 + 1)) console.log(getParams((param1 = 'default') => { return param1 + '.jpeg' })) // [ [ 'param1', undefined ] ] // [ [ 'param1', '\'default\'' ] ]

正如你所知道的，一些参数名消失了，因为Babel转译器将它们从函数中删除了。如果你在最新的NodeJS中运行它，它会像预期的那样工作(注释的结果来自NodeJS)。

另一个注意事项，正如注释中所述，它不能作为默认值与内联箭头函数一起工作。这使得使用RegExp提取值变得非常复杂。

如果这对你有用，请让我知道!很乐意听到一些反馈!

这是我的解决方案——它适用于命名函数和未命名函数，异步和非异步函数，异步和非异步lambdas，以及带和不带paren的lambdas。

const STRIP_COMMENTS = /((\/\/.*$)|(\/\*.*\*\/))/mg;
const STRIP_KEYWORDS = /(\s*async\s*|\s*function\s*)+/;
const ARGUMENT_NAMES = /\(([^)]+)\)\s*=>|([a-zA-Z_$]+)\s*=>|[a-zA-Z_$]+\(([^)]+)\)|\(([^)]+)\)/;
const ARGUMENT_SPLIT = /[ ,\n\r\t]+/;
function getParamNames(func) {
    const fnStr = func.toString()
        .replace(STRIP_COMMENTS, "")
        .replace(STRIP_KEYWORDS, "")
        .trim();
    const matches = ARGUMENT_NAMES.exec(fnStr);
    var match;
    if (matches) {
        for (var i = 1; i < matches.length; i++) {
            if (matches[i]) {
                match = matches[i];
                break;
            } 
        }
    }
    if (match === undefined) {
        return [];
    }
    return match.split(ARGUMENT_SPLIT).filter(part => part !== "");
}

下面是来自AngularJS的代码，它在依赖注入机制中使用了这种技术。

以下是来自http://docs.angularjs.org/tutorial/step_05的解释

Angular的依赖注入器为你的控制器提供服务 当控制器被构造时。依赖注入器 负责创建服务可能的任何传递依赖项 拥有(服务通常依赖于其他服务)。 注意，参数的名称是重要的，因为注入器 使用这些来查找依赖项。

/**
 * @ngdoc overview
 * @name AUTO
 * @description
 *
 * Implicit module which gets automatically added to each {@link AUTO.$injector $injector}.
 */

var FN_ARGS = /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
var FN_ARG_SPLIT = /,/;
var FN_ARG = /^\s*(_?)(.+?)\1\s*$/;
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
function annotate(fn) {
  var $inject,
      fnText,
      argDecl,
      last;

  if (typeof fn == 'function') {
    if (!($inject = fn.$inject)) {
      $inject = [];
      fnText = fn.toString().replace(STRIP_COMMENTS, '');
      argDecl = fnText.match(FN_ARGS);
      forEach(argDecl[1].split(FN_ARG_SPLIT), function(arg){
        arg.replace(FN_ARG, function(all, underscore, name){
          $inject.push(name);
        });
      });
      fn.$inject = $inject;
    }
  } else if (isArray(fn)) {
    last = fn.length - 1;
    assertArgFn(fn[last], 'fn')
    $inject = fn.slice(0, last);
  } else {
    assertArgFn(fn, 'fn', true);
  }
  return $inject;
}

从@jack-allan中得到答案，我稍微修改了函数，以允许ES6的默认属性，如:

function( a, b = 1, c ){};

仍然返回['a'， 'b']

/**
 * Get the keys of the paramaters of a function.
 *
 * @param {function} method  Function to get parameter keys for
 * @return {array}
 */
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
var ARGUMENT_NAMES = /(?:^|,)\s*([^\s,=]+)/g;
function getFunctionParameters ( func ) {
    var fnStr = func.toString().replace(STRIP_COMMENTS, '');
    var argsList = fnStr.slice(fnStr.indexOf('(')+1, fnStr.indexOf(')'));
    var result = argsList.match( ARGUMENT_NAMES );

    if(result === null) {
        return [];
    }
    else {
        var stripped = [];
        for ( var i = 0; i < result.length; i++  ) {
            stripped.push( result[i].replace(/[\s,]/g, '') );
        }
        return stripped;
    }
}

我不知道这个解决方案是否适合您的问题，但它允许您重新定义任何您想要的函数，而无需更改使用它的代码。现有调用将使用定位参数，而函数实现可能使用“命名参数”(单个散列参数)。

我认为你无论如何都会修改现有的函数定义，所以，为什么不拥有一个工厂函数，让你想要的东西:

<!DOCTYPE html>

<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
var withNamedParams = function(params, lambda) {
    return function() {
        var named = {};
        var max   = arguments.length;

        for (var i=0; i<max; i++) {
            named[params[i]] = arguments[i];
        }

        return lambda(named);
    };
};

var foo = withNamedParams(["a", "b", "c"], function(params) {
    for (var param in params) {
        alert(param + ": " + params[param]);
    }
});

foo(1, 2, 3);
</script>
</head>
<body>

</body>
</html>

希望能有所帮助。

这很简单。

At the first there is a deprecated arguments.callee — a reference to called function. At the second if you have a reference to your function you can easily get their textual representation. At the third if you calling your function as constructor you can also have a link via yourObject.constructor. NB: The first solution deprecated so if you can't to not use it you must also think about your app architecture. If you don't need exact variable names just use inside a function internal variable arguments without any magic.

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Functions_and_function_scope/arguments/callee

它们都将调用toString并将其替换为re，这样我们就可以创建一个helper:

// getting names of declared parameters
var getFunctionParams = function (func) {
    return String(func).replace(/[^\(]+\(([^\)]*)\).*/m, '$1');
}

一些例子:

// Solution 1. deprecated! don't use it!
var myPrivateFunction = function SomeFuncName (foo, bar, buz) {
    console.log(getFunctionParams(arguments.callee));
};
myPrivateFunction (1, 2);

// Solution 2.
var myFunction = function someFunc (foo, bar, buz) {
    // some code
};
var params = getFunctionParams(myFunction);
console.log(params);

// Solution 3.
var cls = function SuperKewlClass (foo, bar, buz) {
    // some code
};
var inst = new cls();
var params = getFunctionParams(inst.constructor);
console.log(params);

享受与JS!

UPD:实际上杰克·艾伦提供了一个更好的解决方案。GJ杰克!