javascript - 如何使用 Javascript 获取作为参数传递的函数名称以用于回调目的

Question

我有以下代码示例来获取在参数中传递的函数名称以用于回调目的。

var operation = {
    display : function(fun) {
        console.log('operation "'+ fun.toString() +'" performing' );
        //here i am getting
        /*operation "function () { 
                console.log('operation "subtraction" performed' ); }" performing
        */
        // **instead of entire function i would like to get only method name**
        fun.call();
    },
    addition : function() {
        console.log('operation "addition" performed' );
    },
    subtraction : function() {
        console.log('operation "subtraction" performed' );
    },
    multiplication : function() {
        console.log('operation "multiplication" performed' );
    }
}
operation.display(operation.subtraction);
//Output should be
// operation "subtraction" performing
// operation "subtraction" performed
operation.display(operation.multiplication);
//Output should be
// operation "multiplication" performing
// operation "multiplication" performed
operation.display(operation.addition);
//Output should be
// operation "addition" performing
// operation "addition" performed

Answer 1

您的函数是匿名的；即它们是无名函数表达式。在获得他们的名字之前，您必须先给他们起名字。

var o = {
    foo: function bar() {} // named function expression, name is "bar"
};
function getName(fn) {
    return fn.name;
}
getName(o.foo); // "bar"

但是，这些函数在您的操作对象中确实有相关的键，但您无法找出对象的哪个键>对象某些事情是肯定的，查找匹配的代码将是猜测，因为值不必是唯一的。

function guessKey(val, obj) {
    var key;
    for (key in obj)
        if (obj[key] === val)
            return key;
    return null;
}
guessKey(o.foo, o); // "foo"

<小时/>

Function.prototype.name IE9+ 的垫片(也可能是 8；不确定)

if (Function.prototype.name === undefined) { // may be "" so can't use !
    Object.defineProperty(Function.prototype, "name", {
        get: function () {
                var s = Function.prototype.toString.call(this);
                return s.slice(9, s.indexOf('('));
            }
    });
}