Removing an element from an array using the delete method

Question

Removing an element from an array using the delete method

Here's the scenario:

var object = {key: value, key1: value, key2: value}
var array = [{object}, {object1}, {object2}, {object3}]

I'm looking to remove object 3 and 4 from the array using their key2 values with the Parse JavaScript SDK. How can I achieve this?

I've tried something like this:

object.remove("the key", [object2value2, object3value2])

I need further clarification on specifying the key and the value. Despite going through the documentation repeatedly, I'm unable to get it right. Any help would be appreciated as I'm new to this and struggling!

This is the output in my terminal after running my Parse queries when I use LIST.GET("OBJECT"); I want to delete objects based on their _id. Towards the end, you'll see 'false' where I attempt LIST.REMOVE("_id", [array of _ids]):

[ { _account: 'YzzrzBrO9OSzo6BXwAvVuL5dmMKMqkhOoEqeo',
    _id: 'QllVljV252iNZej9VQgBCYkEyD4Do9fvZMAvmK',
    amount: 2307.15,
    category: [ 'Shops', 'Computers and Electronics' ],
    category_id: '19013000',
    date: '2014-06-23',
    meta: { location: [Object] },
    name: 'Apple Store',
    pending: false,
    score: { location: [Object], name: 0.2 },
    type: { primary: 'place' } },
  { _account: 'V66V6EVOpOIVGQEkNpX1HkwDKX0XWLUga5B2Y',
    _id: 'NQQVQJVDgDhj90JvnXkMt1jm06eqzji5JvO52Z',
    amount: 3.19,
    category: [ 'Food and Drink', 'Restaurants', 'Coffee Shop' ],
    category_id: '13...
    .
    .
    . (remaining content)
]
false

javascript parse-platform

Answer 1

Answer №1

If you want to remove an object from an array, first make sure the operand matches the object to be removed. Begin by locating the object you wish to eliminate...

var array = myObject.get("theArrayCol");
var removeMe;
for (var i=0; i < array.length; i++) {
    if (array[i].key2 == "this one should be removed")
        removeMe = array[i];
}

Then proceed with the removal process...

myObject.remove("theArrayCol", removeMe);

EDIT - Taking our conversation into consideration, here's how you can implement this in your specific scenario. I've broken down the code into simpler functions for easier understanding and improved programming practice...

// Use token as a key to search the Transaction table on parse
function transactionWithToken(token) {
    var query = new Parse.Query("Transactions");
    query.equalTo("access_token", token); 
    query.select("transactions");
    return query.first();
}

// The array represents the value of the array column on the Transaction table
// transactionId is a string that may match the _id property value in the array of objects
function transactionInArrayWithId(array, transactionId) {
    for (var i=0; i<array.length; i++) {
        if (array[i]._id == transactionId) return array[i];
    }
    return undefined;
}

function removeTransactionWithId(transaction, transactionId) {
    var array = transaction.get("transactions");
    var t = transactionInArrayWithId(array, transactionId);
    transaction.remove("transactions", t);
}

// Use token as the key for the Transaction table
// transactionIds is an array of ids to remove from the Transaction object's transactions array
function removeTransactionsWithIdsFromToken(token, transactionIds) {
    return transactionWithToken(token).then(function(result) {
        for (var i=0; i<transactionIds.length; i++) {
            removeTransactionWithId(result, transactionIds[i]);
        }
        return result.save();
    });
}

The distinction between the column name and the table name could improve clarity. Additionally, underscorejs can greatly assist in managing arrays effectively.

Answer 2

If you want to remove an object from an array, first make sure the operand matches the object to be removed. Begin by locating the object you wish to eliminate...

var array = myObject.get("theArrayCol");
var removeMe;
for (var i=0; i < array.length; i++) {
    if (array[i].key2 == "this one should be removed")
        removeMe = array[i];
}

Then proceed with the removal process...

myObject.remove("theArrayCol", removeMe);

EDIT - Taking our conversation into consideration, here's how you can implement this in your specific scenario. I've broken down the code into simpler functions for easier understanding and improved programming practice...

// Use token as a key to search the Transaction table on parse
function transactionWithToken(token) {
    var query = new Parse.Query("Transactions");
    query.equalTo("access_token", token); 
    query.select("transactions");
    return query.first();
}

// The array represents the value of the array column on the Transaction table
// transactionId is a string that may match the _id property value in the array of objects
function transactionInArrayWithId(array, transactionId) {
    for (var i=0; i<array.length; i++) {
        if (array[i]._id == transactionId) return array[i];
    }
    return undefined;
}

function removeTransactionWithId(transaction, transactionId) {
    var array = transaction.get("transactions");
    var t = transactionInArrayWithId(array, transactionId);
    transaction.remove("transactions", t);
}

// Use token as the key for the Transaction table
// transactionIds is an array of ids to remove from the Transaction object's transactions array
function removeTransactionsWithIdsFromToken(token, transactionIds) {
    return transactionWithToken(token).then(function(result) {
        for (var i=0; i<transactionIds.length; i++) {
            removeTransactionWithId(result, transactionIds[i]);
        }
        return result.save();
    });
}

The distinction between the column name and the table name could improve clarity. Additionally, underscorejs can greatly assist in managing arrays effectively.

Answer 3

Answer №2

One way to manipulate this data is by using the filter method. For instance, if you wish to eliminate all objects where the key 'k3' has a value of 3;

var obj1 = {k1: 1, k2: 2, k3: 3};
var obj2 = {k1: 4, k2: 5, k3: 6};
var obj3 = {k1: 7, k2: 8, k3: 9};
var array = [obj1, obj2, obj3];

var unwantedValue = 3;
var result = array.filter(function(obj){
    return obj.k3 !== unwantedValue;
});

Answer 4

One way to manipulate this data is by using the filter method. For instance, if you wish to eliminate all objects where the key 'k3' has a value of 3;

var obj1 = {k1: 1, k2: 2, k3: 3};
var obj2 = {k1: 4, k2: 5, k3: 6};
var obj3 = {k1: 7, k2: 8, k3: 9};
var array = [obj1, obj2, obj3];

var unwantedValue = 3;
var result = array.filter(function(obj){
    return obj.k3 !== unwantedValue;
});

Removing an element from an array using the delete method

Answer №1

Answer №2

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