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up vote 7 down vote favorite

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!"
 }
]
share|improve this question
    
what is your question? Do you have any problem doing it? – Nadir 21 hours ago
    
@Nadir I state at the bottom what my result needs to be. Obviously I cannot achieve it. – mosmic 21 hours ago
up vote 4 down vote accepted

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.
share|improve this answer
    
What if I want my message5 to be an object instead of an array? – mosmic 20 hours ago
    
@mosmic Then approach for that would be different. do you want me to write it now? :) – Rajaprabhu Aravindasamy 20 hours ago
    
If you don't mind, it would be helpful. – mosmic 15 hours ago
    
@mosmic Can you show me what is the expected result? Just give a sample – Rajaprabhu Aravindasamy 15 hours ago
    
message5 = {{"id":5,"body":"ciao!"}} – mosmic 12 hours ago
up vote 2 down vote

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));

share|improve this answer
up vote 2 down vote

try

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

   return value.id == 5;

} );
share|improve this answer
up vote 2 down vote

Use Array filter() method

messages.filter(function(msg){return msg['id'] === 5})
share|improve this answer
up vote 2 down vote

An approach completely 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.com/jquery-1.11.3.min.js"></script>


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

share|improve this answer
1  
This is what I had in mind. Obviously filter function simplifies everything, but your answer is very helpful because I see my mistake now. – mosmic 20 hours ago

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