JavaScript-使用数组名称创建新的（全局）对象

Question

i am trying to create new Objects with names out of an array. Without an array i would do:

var object_bruno = new Object();
var object_carlos = new Object();
var object_luci = new Object();

so i will end up with 3 new Objects. But why wont we do that with an loop, which makes it more easy to adde some more Objects later. So i ttried:

//      an array full of object names
var obj_arr = [ "object_bruno", "object_carlos", "object_luci"];

//      Method one:
for (x in obj_arr) {
    alert(obj_arr[x]);      //  right names shown
    var obj_arr[x] = new Object();  //syntax error, dosent work??
};

//      Method two:
obj_arr.forEach(function(func_name) {
    alert(func_name);       //  right names
    var func_name = new Object();   //  no objects are created ???
});

basicly i would prefer to use Method two. i like it because i can fill them late the same way? hopefuly? Any ideas what wents wrong?

Answer 1

You can just loop over the array and assign a new Object to each of the items , like this:

for (var i = 0, l = obj_arr.length; i < l; i++) {
    obj_arr[i] = {};
}

UPDATE

You can also do it in this way by applying properties to the global object, for example window :

var people = [ "object_bruno", "object_carlos", "object_luci"];

for (var i = 0, l = people.length; i < l; i++) {
    global[people[i]] = {};
}

Using this solution makes the objects global, so you can use them like object_bruno .

Another improvement can be the usage of computed propertiey names of ECMAScript 2015:

var people = [ "bruno", "carlos", "luci"], prefix = 'object_';

for (var i = 0, l = people.length; i < l; i++) {
    global[prefix + people[i]] = {};
}

This allows to have more meaningful array.

Note, the global can be the window object in browsers or global object in NodeJS, or perhaps something else in other environments.

Answer 2

Because you are creating a new variable by declaring

obj_arr.forEach(function(func_name) {
    alert(func_name);       //  right names
    var func_name = new Object();   //  no objects are created ???
});

try this

obj_arr.forEach(function(func_name) {
        alert(func_name);       //  right names
        func_name = new Object();   //  no objects are created ???
    });

Answer 3

var obj_arr = [ "object_bruno", "object_carlos", "object_luci"];

obj_arr.forEach(function(func_name, index, arr) { 
    arr[index] = {}; 
});