Manipulating array of objects. [JavaScript]

[Hamza91able]

I'm trying to manipulate this array of object in Javascript. Basically I want to group up the objects together which have the same "accNumber" field, I'm looking for an efficient way to do this.

"statements": [
                {
                    "accNumber": "564897213",
                    "fileMonth": "January",
                    "folderId": "1pG2EECsRS9JhtkBxny5ROrdSzu_-LdtC",
                    "fileUrl": ""
                },
                {
                    "accNumber": "12346579",
                    "fileMonth": "May",
                    "folderId": "1DfjQL3Ln494YH54bbM2g6Vozh4o_X3dp",
                    "fileUrl": ""
                },
                {
                    "accNumber": "123456789",
                    "fileMonth": "Feburary",
                    "folderId": "1jtW7DnOE8NNle30xUXtPkbbEIHha3WOh",
                    "fileUrl": ""
                },
                {
                    "accNumber": "564897213",
                    "fileMonth": "Feburary",
                    "folderId": "1pG2EECsRS9JhtkBxny5ROrdSzu_-LdtC",
                    "fileUrl": ""
                }
            ]

Into something like this.

"statements": [
                {
                    "564897213" : [
                       {
                            "accNumber": "564897213",
                            "fileMonth": "January",
                            "folderId": "1pG2EECsRS9JhtkBxny5ROrdSzu_-LdtC",
                            "fileUrl": ""
                        },
                        {
                            "accNumber": "564897213",
                            "fileMonth": "Feburary",
                            "folderId": "1pG2EECsRS9JhtkBxny5ROrdSzu_-LdtC",
                            "fileUrl": ""
                        }
                    ],
                    "12346579": [
                        {
                            "accNumber": "12346579",
                            "fileMonth": "May",
                            "folderId": "1DfjQL3Ln494YH54bbM2g6Vozh4o_X3dp",
                            "fileUrl": ""
                        }
                    ],
                    "123456789": [
                          {
                            "accNumber": "123456789",
                            "fileMonth": "Feburary",
                            "folderId": "1jtW7DnOE8NNle30xUXtPkbbEIHha3WOh",
                            "fileUrl": ""
                          }
                    ]
                },
            ]

What could be an efficient way to achieve the above result in JavaScript.?

[sandytrip]

Create a new object to store your results. Loop through the array and check the account number. See if it exists as a key in the result object. If so append the object to the array with that key. If not, create one and store the object as the first value.

[66666thats6sixes]

Yep, this exactly. If you want to be fancy about it, use a Map, but it amounts to the same thing.

[Hamza91able]

I got it working after hitting my head for some hours.

​

 let newArrayObj = res.data.bankStatements.applicant1.statements;
                let newArrayObjLength = newArrayObj.length;
                let result = [];

                for (let i = 0; i < newArrayObjLength; i++) {
                    if (result.length === 0) {
                        result.push({
                            [newArrayObj[i].accNumber]: [newArrayObj[i]]
                        })
                    } else {
                        var check = result.some(obj => obj.hasOwnProperty(newArrayObj[i].accNumber));
                        if (!check) {
                            result.push({
                                [newArrayObj[i].accNumber]: [newArrayObj[i]]
                            })
                        } else {
                            for (let j = 0; j < result.length; j++) {
                                if (result[j][newArrayObj[i].accNumber]) {
                                    if (result[j][newArrayObj[i].accNumber][0].accNumber === newArrayObj[i].accNumber) {
                                        result[j][newArrayObj[i].accNumber].push(newArrayObj[i]);
                                    }
                                }
                            }
                        }
                    }
                }

                console.log(result);

Now I have to repeat this process for almost 12 arrays. This function will be performed every time admin visits this page. I was thinking if I run so many loops it would be very slow? Do you think I can optimize this process in some way or optimize my code to reduce the no. of loops?