I want to iterate over the elements of an array and if a condition is true I want to create a new array.

Example: I have an array called Messages whose elements are objects and I want to check if the id attribute equals 5. If yes create a new array only consisting of this object.

messages = [{
  "id": 10,
  "body": "hello!"
}, {
  "id": 21,
  "body": "hola!"
}, {
  "id": 5,
  "body": "ciao!"
}];

var message5 = [];
var dataObj = {};

$.each(messages, function(index, value) {
  if (value.id == 5) {
    dataObj[index] = value;
  }
});

message5.push(dataObj[index]);

I want my result to be:

message5 = [
 {
  "id": 5,
  "body": "ciao!"
 }
]    

I want to iterate over the elements of an array and if a condition is true I want to create a new array.

Example: I have an array called Messages whose elements are objects and I want to check if the id attribute equals 5. If yes create a new array only consisting of this object.

messages = [{
  "id": 10,
  "body": "hello!"
}, {
  "id": 21,
  "body": "hola!"
}, {
  "id": 5,
  "body": "ciao!"
}];

var message5 = [];
var dataObj = {};

$.each(messages, function(index, value) {
  if (value.id == 5) {
    dataObj[index] = value;
  }
});

message5.push(dataObj[index]);

I want my result to be:

message5 = [
 {
  "id": 5,
  "body": "ciao!"
 }
]    

• javascript
• jquery
• arrays

• what is your question? Do you have any problem doing it? – Nadir Commented Mar 10, 2016 at 13:17
• @Nadir I state at the bottom what my result needs to be. Obviously I cannot achieve it. – Dimitrios Vythoulkas Commented Mar 10, 2016 at 13:26

5 Answers 5

Try to use Array.prototype.filter at this context,

var message5 = messages.filter(function(itm){
  return itm.id == 5;
});

console.log(message5);  //[{"id": 5,"body": "ciao!"}] 

If you want it to be more concise then you could use ES6 Arrow function,

var message5 = messages.filter(itm => itm.id == 5);
console.log(message5);  //[{"id": 5,"body": "ciao!"}]

But note that, the above code is similar to,

var message5 = messages.filter(function(itm){
  return itm.id == 5;
}.bind(this)); //Arrow function will automatically bind its lexical scope to it.

try to use filter:

var messages = [{
  "id": 10,
  "body": "hello!"
}, {
  "id": 21,
  "body": "holla!"
}, {
  "id": 5,
  "body": "ciao!"
}];
var message5 = messages.filter(function(message) {
  return message.id == 5;
});
alert(JSON.stringify(message5));

try

var newArr = messages.filter( function(value){

   return value.id == 5;

} );

Use Array filter() method

messages.filter(function(msg){return msg['id'] === 5})

An approach pletely in jQuery could be:

$(function () {
  var messages = [{
    "id": 10,
    "body": "hello!"
  }, {
    "id": 21,
    "body": "holla!"
  }, {
    "id": 5,
    "body": "ciao!"
  }];
  var dataObj = [];

  $.each(messages, function (index, value) {
    if (value.id == 5) {
      dataObj.push(messages[index]);
    }
  });
  $('#result').text(JSON.stringify(dataObj, 4, 4));
});

<script src="http://code.jquery./jquery-1.11.3.min.js"></script>


<textarea id="result" style="width: 250px;height: 100px"></textarea>