How to remove array for an array by key name

Question

I'd like to manipulate a little bit my data, and specifically, I'd like to remove some keys (array within another array) if its name includes something.

For example, let's say this is my data:

var myArray = [{
    "toDelete_item1": [],
    "name": "Joe"
}, {
    "toDelete_item2": [],
    "name": "Adam"
}, {
    "name": "Peter",
    "toDelete_item3": []
}]

So now I want to exclude from my array all keys which include "toDelete_" in their name.

So I can have something like that:

var myArray = [{
    "name": "Joe"
}, {
    "name": "Adam"
}, {
    "name": "Peter"
}]

Is this possible?

Yes it is. What specifically are you having problems with? How to remove an element from an array? How to check whether an object contains a property with a specific name (or part of)? — Felix Kling, Sep 14 '15 at 08:11
I'm just want to have the same result with out all the "toDelete_*" arrays within myArray — Vassilis Pits, Sep 14 '15 at 08:11
So you just want to delete the property and not actually the whole element? — Felix Kling, Sep 14 '15 at 08:12
yes for example from my first object "toDelete_item1": [] must be removed. — Vassilis Pits, Sep 14 '15 at 08:14
Well, part of your question is a duplicate of http://stackoverflow.com/q/208105/218196. I'm sure the other part has been asked as well already. — Felix Kling, Sep 14 '15 at 08:15
No Felix it's not the same i have already check this question. check my wanted result — Vassilis Pits, Sep 14 '15 at 08:15
Also my object name as you can see it's not fixed it's dynamic it does just include something common — Vassilis Pits, Sep 14 '15 at 08:16
*"it's not the same"* You want to remove a property and that question tells you how. The only difference is that you have to find the name of the property first. — Felix Kling, Sep 14 '15 at 08:17

DavidDomain · Accepted Answer · 2015-09-14T09:10:46.957

Here is what you can do to delete all toDelele_... properties. Using the array.prototype.forEach to iterate over the array, then look for a match of toDelete as a property within every obj.

If there is a match, delete the property.

var data =  [
    {
        "toDelete_item1": [],
        "name": "Joe"
    },
    {
        "toDelete_item2": [],
        "name": "Adam"
    },
    {
        "name": "Peter",
        "toDelete_item3": []
    }
];


data.forEach(function(item,index){
    for(var prop in item) { 
        if (prop.match(/toDelete/) !== null) {
            delete item[prop];    
        }
    }
});

console.log(data);

As mentioned in the comments that this solution will only work for the given scenario, lets turn this into a more usable function. Which will only delete properties within an object which is an item of the data array. Not recursively though.

I don't see the need of checking if the property exists, either there is a match or not (pleas correct me if i am wrong). Sticking with match other than indexOf seems to be just a bit more flexible.

var data =  [
    {"toDelete_item1": [], "name": "Joe"},
    {"toDelete_item2": [], "name": "Adam"},
    {"name": "Peter", "toDelete_item3": []},
    ["toDelete_item4", "Foo"],
    "toDelete_item5"
];

function delPropFromObjsInArr (reg, arr) {
    var regex = new RegExp(reg);
    arr.forEach(function(item, index){
        if (item === Object(item)) {
            for(var p in item) { 
                if (p.match(regex) !== null) {
                    delete item[p];    
                }
            }            
        }
    });    
}

delPropFromObjsInArr("toDelete", data);
console.log(data);

@Felix Kling - You are actually right, no need to use filter here, let me correct this. — DavidDomain, Sep 14 '15 at 08:21
@Felix Kling there is no real need for filter here... and it's just like pain to see filter which creates new array you never use... and its callback doesn't return anything. — Ivan, Sep 14 '15 at 08:24
Although this is correct for given scenario, this solution will fail if they change the key name for the array property. :) — AdityaParab, Sep 14 '15 at 08:25
@AdityaParab - You are right, made an edit. Thanks for the hint. ;-) — DavidDomain, Sep 14 '15 at 09:11

score 0 · Answer 2 · answered Sep 14 '15 at 08:24

It's very simple iteration really and then string checking.

For removing properties of objects you can use the delete keyword.

for iterating through an objects properties use for(propname in object) to do that. If you use an indexed array, propname will be an integer with the current index.

If you have an object with named variables you need to run the test object.hasOwnProperty(propname) so you dont work on native objects or values.

var myArray =  [
        {
            "toDelete_item1": [],
            "name": "Joe"
        },
        {
            "toDelete_item2": [],
            "name": "Adam"
        },
        {
            "name": "Peter",
            "toDelete_item3": []
        }
    ]
 for(var i in myArray) {
   for(var key in myArray[i]) {
     if(myArray[i].hasOwnProperty(key)) {
       if(key.indexOf('toDelete_') === 0) {
         delete myArray[i][key]
         }
       }
     }
   }
console.log(myArray);

score 0 · Answer 3 · answered Sep 14 '15 at 08:25

You will need two loops to go through all your elements in the array, then go through all the properties of the objects, then to delete the one you don't need.

for (var i in myArray) {

    var element = myArray[i];

    for (var prop in element) {
       if (prop.indexOf('toDelete_') == 0) {
          delete element[prop];
       }
    }

}

score -1 · Answer 4 · edited May 23 '17 at 12:03

-1

Use the "delete" keyword in Javascript.

delete myArray["toDelete_item1"];

You might want to perform a search and list the name of keys to be deleted in an array and delete them one by one.

Reference: How do I remove objects from a javascript associative array?

edited May 23 '17 at 12:03

Community

1
1

answered Sep 14 '15 at 08:14

orb

175
2
13

score -1 · Answer 5 · answered Sep 14 '15 at 08:23

-1

Like this?

myArray.forEach( function(current){
    for(var p in current){
        if( current[p].constructor === Array){
            delete current[p];
        }
    }
});

answered Sep 14 '15 at 08:23

AdityaParab

7,024
3
27
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How to remove array for an array by key name

5 Answers5