在具有特定属性的数组中的其他 object 之前插入数组中的 Object

Question

I have one Array with objects. All objects habe one unique id. Now I want to insert a new Object before the object with the specific id. To do that I get this object:

{"topic":"add","payload":{"id":1,"end":"24:00","temp":21,"add":0,"delete":0},"row":-1,"socketid":"SSZY-1C3jiP8-NS2AAAB","_msgid":"a891f409.e30038"}

and now I need to find this object in this array with the id:

[{"woche":"Montag","status":0,"_children":[{"id":1,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Dienstag","status":0,"vortag":1,"_children":[{"id":2,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Mittwoch","start":"","status":0,"vortag":1,"_children":[{"id":3,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Donnerstag","status":0,"vortag":1,"_children":[{"id":4,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Freitag","start":"","status":0,"vortag":1,"_children":[{"id":5,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Samstag","start":"","status":0,"vortag":1,"_children":[{"id":6,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Sonntag","start":"","status":0,"vortag":1,"_children":[{"id":7,"end":"24:00","temp":21,"add":0,"delete":0}]}]

and now I want to insert a new object bofore the object with the matching id.

How can I find the position in the array and how can I add this object?

{"id":`${++Id}`,"end":"","temp":21,"add":0,"delete":0}

At the end it should look like this:

[{"woche":"Montag","status":0,"_children":[{"id":"8","end":"","temp":21,"add":0,"delete":0},{"id":1,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Dienstag","status":0,"vortag":1,"_children":[{"id":2,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Mittwoch","start":"","status":0,"vortag":1,"_children":[{"id":3,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Donnerstag","status":0,"vortag":1,"_children":[{"id":4,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Freitag","start":"","status":0,"vortag":1,"_children":[{"id":5,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Samstag","start":"","status":0,"vortag":1,"_children":[{"id":6,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Sonntag","start":"","status":0,"vortag":1,"_children":[{"id":7,"end":"24:00","temp":21,"add":0,"delete":0}]}]

Answer 1

You can use filter method to check for the index of the specific element.

Suppose this is your array:

let arr = [{"woche":"Montag","status":0,"_children":[{"id":1,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Dienstag","status":0,"vortag":1,"_children":[{"id":2,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Mittwoch","start":"","status":0,"vortag":1,"_children":[{"id":3,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Donnerstag","status":0,"vortag":1,"_children":[{"id":4,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Freitag","start":"","status":0,"vortag":1,"_children":[{"id":5,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Samstag","start":"","status":0,"vortag":1,"_children":[{"id":6,"end":"24:00","temp":21,"add":0,"delete":0}]},{"woche":"Sonntag","start":"","status":0,"vortag":1,"_children":[{"id":7,"end":"24:00","temp":21,"add":0,"delete":0}]}]

You need to search for the index of this object in the array:

let s = {"topic":"add","payload":{"id":1,"end":"24:00","temp":21,"add":0,"delete":0},"row":-1,"socketid":"SSZY-1C3jiP8-NS2AAAB","_msgid":"a891f409.e30038"}

You can use the following query to achieve this:

let index = -1
arr.filter((o) => {
    if(s.payload.id === o._children[0].id) {
        index = arr.indexOf(o)
    }
    return o
})

You can use splice method to add new object in the array at specific index.

arr.splice(index, 0, <value to enter in array>)

Answer 2

You can use flatMap if you are writing for relatively modern web browsers or a node application:

const newItem; // I assume this is your object you want to insert
const fullArray; // I assume this is the full array

const result = fullArray.flatMap(
    item => item.id === "1" ? [newItem, item] : [item]
);

This is to my knowledge the most efficient way to get a new array result that is identical to fullArray except with newItem inserted every time before an item occurs in fullArray that fulfills the condition item.id === "1" .

A short explanation about flatMap : .flatMap(x) is an abbreviation for .map(x).flat() that is more efficient. The idea is that you have eg [a, b, c, d] and .map() it to [[a], [b], [newItem, c], [d]] which is then .flat() tened to [a, b, newItem, c, d] . Although flatMap does this without inefficiently going through both steps but instead does it in one go, so there is not much space for improvement efficiency wise.