JSFiddle - React, Tailwind, and code Playground

JavaScript

var obj = [{
    id: 23,
    name: 'Test1',
    children: [{
         id: 24,
         name: 'Test2',
         children: []
    },{
         id: 25,
         name: 'Test2',
         children: []
    }],
}];

var findNode = function(nodeId, json, o){
    if(o.id == nodeId){
        o.children.push(json);
    }
    else{
        if(o.children){
            for(var i=0; i<o.children.length; i++){
                o.children[i] = findNode(nodeId, json, o.children[i]);
            }
        }
    }
    return o;
};

obj = findNode(24,{
         id: 26,
         name: 'Test2',
         children: []
    }, obj);
console.log (obj);