I have 2 arrays

console.log(this.items) = userGroups

[
    {
        "id": 63,
        "name": "URLGROUP-1643836551908"
    }
]

console.log(urls)

userGroup can have URLs

[
    [
        {
            "id": 110,
            "group_id": 63,
            "url": "https://www.apple.com",
            "url_num": 1,
            "max_iteration": 2
        },
        {
            "id": 111,
            "group_id": 63,
            "url": "https://www.google.com",
            "url_num": 2,
            "max_iteration": 2
        }

    ]
]

I'm trying to combine them like this : id, name, url

[
    {
        "id": 63,
        "name": "URLGROUP-1643836551908",
        "url": [
        {
            "id": 110,
            "group_id": 63,
            "url": "https://www.apple.com",
            "url_num": 1,
            "max_iteration": 2
        },
        {
            "id": 111,
            "group_id": 63,
            "url": "https://www.google.com",
            "url_num": 2,
            "max_iteration": 2
        }

    ]
    }
]

I've tried merge, and I don't get a good result at all. I'm about to do for-loop within a forloop, but that will be bad for performance.

What should I do in case ?

If I do this

for (let i = 0; i < this.items.length; i  ) {
    for (let j = 0; j < urls.length; j  ) {
        if (i == j) {
            this.items[i].urls = urls[j]
        }
    }
}

console.log(this.items)

I kind of get what I want:

[
    {
        "id": 63,
        "name": "URLGROUP-1643836551908",
        "details": [
            {
                "id": 110,
                "group_id": 63,
                "url": "https://www.acme.com",
                "url_num": 1,
                "max_iteration": 2
            }
        ]
    }
]

CodePudding user response：

Although the example is not varied enough to be sure, I will assume that the second array (of arrays) has grouped items with the same group_id value in the same subarray.

You could create a Map keyed by group_id (the first found in a subarray), and assign to each the corresponding subarray.

Then map the first array to objects extended with a url property that is taken from the Map, based on the objects id property:

let userGroups = [{"id": 63,"name": "URLGROUP-1643836551908"}];

let urls = [[{"id": 110,"group_id": 63,"url": "https://www.apple.com","url_num": 1,"max_iteration": 2},{"id": 111,"group_id": 63,"url": "https://www.google.com","url_num": 2,"max_iteration": 2}]];

let urlsMap = new Map(urls.map(arr => [arr[0].group_id, arr]));
let result = userGroups.map(obj => ({...obj, url: urlsMap.get(obj.id)}));

console.log(result);