I'd like to know if are there any way to get field name or property name dynamically inside my jquery.grep function

<script type="text/javascript">
var names = [];
var object = {
    name: "Joe",
    age: 20,
    email: "[email protected]"
};
names.push(object);
object = {
    name: "Mike",
    age: 50,
    email: "[email protected]"
};
names.push(object);
object = {
    name: "Joe",
    age: 45,
    email: "[email protected]"
};
names.push(object);

var found_names = $.grep(names, function(v,y) {
    return v.name === "Mike" && v.age <= 50;
});

$(document).ready(function(){

console.log(found_names);
});

</script>

what i get actually with this code are name and age values according a condition but what about if i wanted to get the key names i.e. name, age, email. Is that possible on my function?

I'd like to know if are there any way to get field name or property name dynamically inside my jquery.grep function

<script type="text/javascript">
var names = [];
var object = {
    name: "Joe",
    age: 20,
    email: "[email protected]"
};
names.push(object);
object = {
    name: "Mike",
    age: 50,
    email: "[email protected]"
};
names.push(object);
object = {
    name: "Joe",
    age: 45,
    email: "[email protected]"
};
names.push(object);

var found_names = $.grep(names, function(v,y) {
    return v.name === "Mike" && v.age <= 50;
});

$(document).ready(function(){

console.log(found_names);
});

</script>

what i get actually with this code are name and age values according a condition but what about if i wanted to get the key names i.e. name, age, email. Is that possible on my function?

• javascript
• jquery

Share Improve this question Follow asked Oct 27, 2015 at 23:42 Cabezz CabezzCabezz Cabezz 2711 silver badge88 bronze badges

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2 Answers 2

Sorted by: Reset to default 4

You can loop through the properties of an object by doing this-

var myObj = { name: "John", age: 28 }

for (var key in myObj) {
    console.log("key: " + key);
    console.log("value: " + myObj[key]);
}

//prints
key: name
value: John
key: age
value: 28

When you used grep you basically created a new array with the objects that has a name "Mike" and are below 50 or equal to 50. In your case you can loop through your new array and print the key and value.

found_names.forEach(function (obj) {
   console.log('Name: ' + obj.name);
   console.log('Age: ' + obj.age);
   console.log('Email: ' + obj.email);
});

If you want the index(key) you can also do

found_names.forEach(function (obj, index) {
       console.log('Index: ' + index);
       console.log('Name: ' + obj.name);
       console.log('Age: ' + obj.age);
       console.log('Email: ' + obj.email);
});

Edit 2 -

If you have a dynamic object where you don't know the keys you can use what Thiago suggested and tweaking it a bit. The example below would loop through every object then would go through its data.

found_names.forEach(function (obj) {
    for(key in obj){
        console.log(key + ': ' + obj[key]);
    }
});

Another example would be using an array like object where you loop through an object like you are looping in an array.

found_names.forEach(function (obj, index, array) {
    array.forEach(function(data){
        // data would be the current index 
        console.log(array[data]);
    });
});

Here is an example on JSFiddle

Source for forEach Docs