带有名称的JavaScript字典

另一种方法是使用一个对象数组，每个单独的对象包含一个列的属性。这稍微改变了"myMappings"的结构，但使它更容易使用:

var myMappings = [
    { title: "Name", width: "10%" },
    { title: "Phone", width: "10%" },
    { title: "Address", width: "50%" },
    { title: "Zip", width: "10%" },
    { title: "Comments", width: "20%" }
];

然后你可以很容易地通过一个for循环遍历所有的"列":

for (var i = 0; i < myMappings.length; i += 1) {
    // myMappings[i].title ...
    // myMappings[i].width ...
}

我看到的主要问题是很难循环遍历，以填充表。

简单地使用数组的数组:

var myMappings = [
    ["Name", "10%"], // Note the quotes around "10%"
    ["Phone", "10%"],
    // etc..
];

…这简化了访问:

myMappings[0][0]; // column name
myMappings[0][1]; // column width

另外:

var myMappings = {
    names: ["Name", "Phone", etc...],
    widths: ["10%", "10%", etc...]
};

和访问:

myMappings.names[0];
myMappings.widths[0];

您可能正在尝试使用JSON对象:

var myMappings = { "name": "10%", "phone": "10%", "address": "50%", etc.. }

myMappings.name;
myMappings.phone;
etc..

从技术上讲，对象是一个字典。

var myMappings = {
    mykey1: 'myValue',
    mykey2: 'myValue'
};
var myVal = myMappings['myKey1'];
alert(myVal); // myValue

你甚至可以循环一个。

for(var key in myMappings) {
    var myVal = myMappings[key];
    alert(myVal);
}

myMappings['mykey3'] = 'my value';

和ContainsKey:

if (myMappings.hasOwnProperty('myKey3')) {
    alert('key already exists!');
}

我建议你这样做:http://javascriptissexy.com/how-to-learn-javascript-properly/

尝试:

var myMappings = {
    "Name":     "10%",
    "Phone":    "10%",
    "Address":  "50%",
    "Zip":      "10%",
    "Comments": "20%"
}
// Access is like this
myMappings["Name"] // Returns "10%"
myMappings.Name // The same thing as above
// To loop through...
for(var title in myMappings) {
    // Do whatever with myMappings[title]
}

我建议不要使用数组，除非你有多个对象要考虑。这句话没有任何问题:

var myMappings = {
    "Name": 0.1,
    "Phone": 0.1,
    "Address": 0.5,
    "Zip": 0.1,
    "Comments": 0.2
};
for (var col in myMappings) {
    alert((myMappings[col] * 100) + "%");
}

在JavaScript中模拟字典的一种比哈希表更简单、更原生、更有效的方法:

它还利用了JavaScript是弱类型的。而是类型推断。

方法如下(摘自Google Chrome控制台):

var myDict = {};
myDict.one = 1;
1
myDict.two = 2;
2
if (myDict.hasOwnProperty('three'))
{
  console.log(myDict.two);
}
else
{
  console.log('Key does not exist!');
}
Key does not exist! VM361:8
if (myDict.hasOwnProperty('two'))
{
  console.log(myDict.two);
}
else
{
  console.log('Key does not exist!');
}
2 VM362:4
Object.keys(myDict);
["one", "two"]
delete(myDict.two);
true
myDict.hasOwnProperty('two');
false
myDict.two
undefined
myDict.one
1

这是一个字典，只要toString()属性返回唯一的值，它就接受任何类型的键。字典使用任何值作为键值对的值。

参见 JavaScript是否会受益于Dictionary Object。

按原样使用字典:

var dictFact = new Dict();
var myDict = dictFact.New();
myDict.addOrUpdate("key1", "Value1");
myDict.addOrUpdate("key2", "Value2");
myDict.addOrUpdate("keyN", "ValueN");

字典代码如下:

/*
* Dictionary Factory Object
* Holds common object functions. similar to V-Table
* this.New() used to create new dictionary objects
* Uses Object.defineProperties so won't work on older browsers.
* Browser Compatibility (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperties)
*      Firefox (Gecko) 4.0 (2), Chrome 5, Internet Explorer 9, Opera 11.60, Safari 5
*/
function Dict() {
    /*
    * Create a new Dictionary
    */
    this.New = function () {
        return new dict();
    };
    /*
    * Return argument f if it is a function otherwise return undefined
    */
    function ensureF(f) {
        if (isFunct(f)) {
            return f;
        }
    }
    function isFunct(f) {
        return (typeof f == "function");
    }
    /*
    * Add a "_" as first character just to be sure valid property name
    */
    function makeKey(k) {
        return "_" + k;
    };
    /*
    * Key Value Pair object - held in array
    */
    function newkvp(key, value) {
        return {
            key: key,
            value: value,
            toString: function () { return this.key; },
            valueOf: function () { return this.key; }
        };
    };
    /*
    * Return the current set of keys.
    */
    function keys(a) {
        // remove the leading "-" character from the keys
        return a.map(function (e) { return e.key.substr(1); });
        // Alternative: Requires Opera 12 vs. 11.60
        // -- Must pass the internal object instead of the array
        // -- Still need to remove the leading "-" to return user key values
        //    Object.keys(o).map(function (e) { return e.key.substr(1); });
    };
    /*
    * Return the current set of values.
    */
    function values(a) {
        return a.map(function(e) { return e.value; } );
    };
    /*
    * Return the current set of key value pairs.
    */
    function kvPs(a) {
        // Remove the leading "-" character from the keys
        return a.map(function (e) { return newkvp(e.key.substr(1), e.value); });
    }
    /*
    * Returns true if key exists in the dictionary.
    * k - Key to check (with the leading "_" character)
    */
    function exists(k, o) {
        return o.hasOwnProperty(k);
    }
    /*
    * Array Map implementation
    */
    function map(a, f) {
        if (!isFunct(f)) { return; }
        return a.map(function (e, i) { return f(e.value, i); });
    }
    /*
    * Array Every implementation
    */
    function every(a, f) {
        if (!isFunct(f)) { return; }
        return a.every(function (e, i) { return f(e.value, i) });
    }
    /*
    * Returns subset of "values" where function "f" returns true for the "value"
    */
    function filter(a, f) {
        if (!isFunct(f)) {return; }
        var ret = a.filter(function (e, i) { return f(e.value, i); });
        // if anything returned by array.filter, then get the "values" from the key value pairs
        if (ret && ret.length > 0) {
            ret = values(ret);
        }
        return ret;
    }
    /*
    * Array Reverse implementation
    */
    function reverse(a, o) {
        a.reverse();
        reindex(a, o, 0);
    }
    /**
    * Randomize array element order in-place.
    * Using Fisher-Yates shuffle algorithm.
    */
    function shuffle(a, o) {
        var j, t;
        for (var i = a.length - 1; i > 0; i--) {
            j = Math.floor(Math.random() * (i + 1));
            t = a[i];
            a[i] = a[j];
            a[j] = t;
        }
        reindex(a, o, 0);
        return a;
    }
    /*
    * Array Some implementation
    */
    function some(a, f) {
        if (!isFunct(f)) { return; }
        return a.some(function (e, i) { return f(e.value, i) });
    }
    /*
    * Sort the dictionary. Sorts the array and reindexes the object.
    * a - dictionary array
    * o - dictionary object
    * sf - dictionary default sort function (can be undefined)
    * f - sort method sort function argument (can be undefined)
    */
    function sort(a, o, sf, f) {
        var sf1 = f || sf; // sort function  method used if not undefined
        // if there is a customer sort function, use it
        if (isFunct(sf1)) {
            a.sort(function (e1, e2) { return sf1(e1.value, e2.value); });
        }
        else {
            // sort by key values
            a.sort();
        }
        // reindex - adds O(n) to perf
        reindex(a, o, 0);
        // return sorted values (not entire array)
        // adds O(n) to perf
        return values(a);
    };
    /*
    * forEach iteration of "values"
    *   uses "for" loop to allow exiting iteration when function returns true
    */
    function forEach(a, f) {
        if (!isFunct(f)) { return; }
        // use for loop to allow exiting early and not iterating all items
        for(var i = 0; i < a.length; i++) {
            if (f(a[i].value, i)) { break; }
        }
    };
    /*
    * forEachR iteration of "values" in reverse order
    *   uses "for" loop to allow exiting iteration when function returns true
    */
    function forEachR(a, f) {
        if (!isFunct(f)) { return; }
        // use for loop to allow exiting early and not iterating all items
        for (var i = a.length - 1; i > -1; i--) {
            if (f(a[i].value, i)) { break; }
        }
    }
    /*
    * Add a new Key Value Pair, or update the value of an existing key value pair
    */
    function add(key, value, a, o, resort, sf) {
        var k = makeKey(key);
        // Update value if key exists
        if (exists(k, o)) {
            a[o[k]].value = value;
        }
        else {
            // Add a new Key value Pair
            var kvp = newkvp(k, value);
            o[kvp.key] = a.length;
            a.push(kvp);
        }
        // resort if requested
        if (resort) { sort(a, o, sf); }
    };
    /*
    * Removes an existing key value pair and returns the "value" If the key does not exists, returns undefined
    */
    function remove(key, a, o) {
        var k = makeKey(key);
        // return undefined if the key does not exist
        if (!exists(k, o)) { return; }
        // get the array index
        var i = o[k];
        // get the key value pair
        var ret = a[i];
        // remove the array element
        a.splice(i, 1);
        // remove the object property
        delete o[k];
        // reindex the object properties from the remove element to end of the array
        reindex(a, o, i);
        // return the removed value
        return ret.value;
    };
    /*
    * Returns true if key exists in the dictionary.
    * k - Key to check (without the leading "_" character)
    */
    function keyExists(k, o) {
        return exists(makeKey(k), o);
    };
    /*
    * Returns value assocated with "key". Returns undefined if key not found
    */
    function item(key, a, o) {
        var k = makeKey(key);
        if (exists(k, o)) {
            return a[o[k]].value;
        }
    }
    /*
    * changes index values held by object properties to match the array index location
    * Called after sorting or removing
    */
    function reindex(a, o, i){
        for (var j = i; j < a.length; j++) {
            o[a[j].key] = j;
        }
    }
    /*
    * The "real dictionary"
    */
    function dict() {
        var _a = [];
        var _o = {};
        var _sortF;
        Object.defineProperties(this, {
            "length": { get: function () { return _a.length; }, enumerable: true },
            "keys": { get: function() { return keys(_a); }, enumerable: true },
            "values": { get: function() { return values(_a); }, enumerable: true },
            "keyValuePairs": { get: function() { return kvPs(_a); }, enumerable: true},
            "sortFunction": { get: function() { return _sortF; }, set: function(funct) { _sortF = ensureF(funct); }, enumerable: true }
        });
        // Array Methods - Only modification to not pass the actual array to the callback function
        this.map = function(funct) { return map(_a, funct); };
        this.every = function(funct) { return every(_a, funct); };
        this.filter = function(funct) { return filter(_a, funct); };
        this.reverse = function() { reverse(_a, _o); };
        this.shuffle = function () { return shuffle(_a, _o); };
        this.some = function(funct) { return some(_a, funct); };
        this.sort = function(funct) { return sort(_a, _o, _sortF, funct); };
        // Array Methods - Modified aborts when funct returns true.
        this.forEach = function (funct) { forEach(_a, funct) };
        // forEach in reverse order
        this.forEachRev = function (funct) { forEachR(_a, funct) };
        // Dictionary Methods
        this.addOrUpdate = function(key, value, resort) { return add(key, value, _a, _o, resort, _sortF); };
        this.remove = function(key) { return remove(key, _a, _o); };
        this.exists = function(key) { return keyExists(key, _o); };
        this.item = function(key) { return item(key, _a, _o); };
        this.get = function (index) { if (index > -1 && index < _a.length) { return _a[index].value; } } ,
        this.clear = function() { _a = []; _o = {}; };
        return this;
    }
    return this;
}