Javascript - creating new object, but not passing any parameters

Question

New to Javascript. Trying to create a datatype (assuming OBJECT is what I am wanting here) definition that can be used between various functions. The definition, as of now, is only variables (no functions etc). The issue I am having is that I want to initially create it, and then later set the properties...

What I would LIKE to do... is have a definition.

// Object Definition
function resultObj = {
    isValid: true,
    nn_name: '',
    account_name: '',
    translated_name: '',
    address1: '',
    city: '',
    state: '',
    zip: '',
    country: '',
    formattedAddress : '',
    auth_string: '',
    error_text: '',
    error_body: '',
    error_type: ''    
};

At some point, I will create an occurrence of that definition.

myData = new resultObj;
... do some processing here...
... set a FEW of the variables
myData.zip = '12345';

How can I create this so that I don't have to pass in all the values (or empty parameters) at creation time?

That is not valid JavaScript...and JavaScript has both constructor functions and optional parameters...and has no concept of user-defined types... — Jared Smith, Aug 11 '16 at 15:49
As @JaredSmith said it is not valid, but if you want to continue with your structure you should check [Object.assign](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign). [Browser Support](http://kangax.github.io/compat-table/es6/#test-Object_static_methods_Object.assign) — Bhavik, Aug 11 '16 at 15:54

score 3 · Accepted Answer · edited May 23 '17 at 11:44

How about you create your original default/initial object and then whenever you have to create an another new/independent object with the very same initial properties, you just copy that old object in new one?

var myData = Object.assign({}, resultObj);

You can use Object.assign to create an exact copy.

The Object.assign() method is used to copy the values of all enumerable own properties from one or more source objects to a target object. It will return the target object.

var resultObj = {
    isValid: true,
    nn_name: '',
    account_name: '',
    translated_name: '',
    address1: '',
    city: '',
    state: '',
    zip: '',
    country: '',
    formattedAddress : '',
    auth_string: '',
    error_text: '',
    error_body: '',
    error_type: ''    
};

var myData = Object.assign({}, resultObj);
document.write(JSON.stringify(myData));

Also see: How do I correctly clone a JavaScript object?

As an added bonus, its trivial to polyfill even in IE – Jared Smith Aug 11 '16 at 15:55 — Jared Smith, Aug 11 '16 at 15:55

score 0 · Answer 2 · answered Aug 11 '16 at 15:50

0

It's not necessary to define all the potential properties on an object:

function resultObj(){}
var result = new resultObj()
result.zip = 12345
console.log(result.zip) //=> 12345

answered Aug 11 '16 at 15:50

jshawl

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Although perf is rarely an issue, not defining all the properties at construction time (even if they default to null) means property access is an order of magnitude slower... – Jared Smith Aug 11 '16 at 15:54

score 0 · Answer 3 · answered Aug 11 '16 at 18:16

You could use something like this:

var getResultObj = function(param1, param2) {
    var one = param2 ? param2 : '';
    var two = param2 ? param2 : '';

    var objectToBeReturned = {
        isValid: true,
        nn_name: one,
        account_name: two,
        translated_name: '',
        address1: '',
        city: '',
        state: '',
        zip: '',
        country: '',
        formattedAddress : '',
        auth_string: '',
        error_text: '',
        error_body: '',
        error_type: ''
      };

      return getResultObj;
};

Every time you call getResultObj(); it returns a new instance of your object. But you could also use any other Constructor Pattern pattern.

Javascript - creating new object, but not passing any parameters

3 Answers3