CODEWITHSUNDEEP
javascript
user6747084
user6747084

Reputation:

How to filter object using some array?

I have to filter the object based on the values of array.

This is my object 

$scope.myObj = {
    en_US: "English",
    es_ES: "Spanish",
    pt_PT: "Portuguese",
    fr_FR: "French",
    de_DE: "German"
}

This is my array 

$scope.myArr=["en_US","es_ES"]

I want to filter my object using my array? How to do that in efficient way? Thanks in advance.

Upvotes: 2

Views: 100

Answers (5)

Matías Fidemraizer
Matías Fidemraizer

Reputation: 64933

Probably you're looking to match those ISO language codes found in myArr against myObj. Hence, Array.prototype.map should be enough:

var myArr = ["en_US", "es_ES"];

var myObj = {
  en_US: "English",
  es_ES: "Spanish",
  pt_PT: "Portuguese",
  fr_FR: "French",
  de_DE: "German"
};

var matchedLangs = myArr.map(lang => ({
  [lang]: myObj[lang]
}));

console.log(matchedLangs);

This approach will give you an array of objects where properties are the ISO language codes and the property values their English name.

If you're looking for an object result, let's add Array.prototype.reduce:

var myArr = ["en_US", "es_ES"];

var myObj = {
  en_US: "English",
  es_ES: "Spanish",
  pt_PT: "Portuguese",
  fr_FR: "French",
  de_DE: "German"
};

// #1 Array.prototype.map returns an array of matched language codes to 
// their english names
// 
// #2 Array.prototype.reduce receives the array from #1 and transforms it
// creating a new "result" object. Object.assign mixes the "match" object 
// (an object whose property is the ISO code and the value the English name)
// with the "result" object, which represents the accumulated result
var matchedLangs = myArr.map(lang => ({
  [lang]: myObj[lang]
})).reduce((result, match) => Object.assign(result, match));

console.log(matchedLangs);

// Everything can be also be simplified to just use Array.prototype.reduce:
var matchedLangs2 = myArr.reduce((result, lang) =>
  Object.assign(result, {
    [lang]: myObj[lang]
  }), {});

console.log(matchedLangs2);

What's the { [blah]: "x" } thing?

Since ECMA-Script 2015, you can declare properties using non-literal values.

See the following snippet:

var propertyName = "hello";

var obj = { [propertyName]: "world" };

console.log(obj);

Upvotes: 0

Nina Scholz
Nina Scholz

Reputation: 386540

You could iterate the given keys and build a new object.

var $scope = {}, result;

$scope.myObj = { en_US: "English", es_ES: "Spanish", pt_PT: "Portuguese", fr_FR: "French", de_DE: "German" };
$scope.myArr = ["en_US", "es_ES"];

result = $scope.myArr.reduce(function (o, k) {
    o[k] = $scope.myObj[k];
    return o;
}, {});

console.log(result);

ES6 with Object.assign

var $scope = {}, result;

$scope.myObj = { en_US: "English", es_ES: "Spanish", pt_PT: "Portuguese", fr_FR: "French", de_DE: "German" };
$scope.myArr = ["en_US", "es_ES"];

result = $scope.myArr.reduce((o, k) => Object.assign(o, { [k]: $scope.myObj[k] }), {});

console.log(result);

Even shorter with ES6, Array#map and spread syntax ....

var $scope = {}, result;

$scope.myObj = { en_US: "English", es_ES: "Spanish", pt_PT: "Portuguese", fr_FR: "French", de_DE: "German" };
$scope.myArr = ["en_US", "es_ES"];

result = Object.assign(...$scope.myArr.map(k => ({ [k]: $scope.myObj[k] })));

console.log(result);

Upvotes: 3

mahesh peddi
mahesh peddi

Reputation: 797

You can use Array.prototype.filter() function like

myArr.filter(function (o, k) {
o[k] = myObj[k];
return o;
}, {});

This will give result like [0:"en_US",1:"es_ES"]

refer this https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/filter for more information

Upvotes: 0

cnorthfield
cnorthfield

Reputation: 3501

As you appear to be using AngularJS you can use the angular.forEach function:

var myObj = {
  en_US: "English",
  es_ES: "Spanish",
  pt_PT: "Portuguese",
  fr_FR: "French",
  de_DE: "German"
};

var myArr = ["en_US", "es_ES"];

angular.forEach(myObj, function(value, key) {

  // if the key doesn't appear in `myArr` delete the key-pair from the object
  if (myArr.indexOf(key) === -1) {

    // delete the property from the object
    delete myObj[key];

  }

});

console.log(myObj);
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

Upvotes: 0

kind user
kind user

Reputation: 41893

You can use Array.prototype.reduce() to get the desired result.

var myObj = {en_US: "English", es_ES: "Spanish", pt_PT: "Portuguese", fr_FR: "French", de_DE: "German"},
    myArr = ["en_US","es_ES"];
    
    myObj = Object.keys(myObj).reduce(function(s,a) {
      if (myArr.indexOf(a) == -1) {
        s[a] = myObj[a];
      }
      return s;
    }, {});
    
    console.log(myObj);

Upvotes: 0

Related Questions