将元素插入同一数组中的另一个元素内

Question

I've been looking for a solution for this with no luck. I have an JSON object:

arr = [
{
    "id": "1",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "2",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "3", 
    "dataId" : "", 
    "rel": ""   
}, 
{
    "id": "4",
    "dataId" : "1", 
    "rel": ""   
}];

I need a way to manipulate this array with javascript (jquery is allowed), so when "arr[a].dataId" match with the "arr[b].id", take "arr[a]" element and insert into "arr[b]" creating a new array like this:

newArr = [
{
    "id": "1",
    "dataId" : "", 
    "rel" : [
        {
            "id": "4",
            "dataId" : "1"  
        }
    ]
}, 
{
    "id": "2",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "3", 
    "dataId" : "", 
    "rel": ""   
}

];

I hope you understand what I'm asking, any help will be appreciated. Thanks in advance

Answer 1

Try this:

var arr = [
{
    "id": "1",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "2",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "3", 
    "dataId" : "", 
    "rel": ""   
}, 
{
    "id": "4",
    "dataId" : "1", 
    "rel": ""   
}];
$(arr).each(function(index,value){
     if(value.dataId)
     {
         $(arr).each(function(ind,val){
             if(val.id==value.dataId)
             {
                 if(val.rel)
                 {
                     val.rel.push({"id":value.id,"dataId":value.dataId});
                 }
                 else
                 {                   
                     val.rel=[{"id":value.id,"dataId":value.dataId}];                     
                 }
             }
         });
     }
});
console.log(arr);

Fiddle http://jsfiddle.net/7g23B/

Answer 2

This one does move the elements and doesn't manipulate the array while it's iterating over it. Also doesn't need to extend the Array.prototype. One downside is that you're going to get holes in your array (indexes of elements won't be 0 to length-1), but from what I can see it's not important in your use case.

var arr = [
{
    "id": "1",
    "dataId" : "", 
    "rel": ""
}, 
{
    "id": "2",
    "dataId" : "3", 
    "rel": ""
}, 
{
    "id": "3", 
    "dataId" : "", 
    "rel": ""   
}, 
{
    "id": "4",
    "dataId" : "1", 
    "rel": ""   
}];

var indexesToMoveMap = {};

$.each(arr, function(outerIndex, outerElem) {
    if (outerElem.dataId) { 
        $.each(arr, function(innerIndex, innerElem) {
            if (innerElem.id === outerElem.dataId) {
                indexesToMoveMap[outerIndex] = innerIndex;
            }
        });
    }
});

$.each(indexesToMoveMap, function(indexToMove, indexToMoveTo) {
    arr[indexToMoveTo].rel = arr[indexToMoveTo].rel || [];
    arr[indexToMoveTo].rel.push(arr[indexToMove]);
    delete arr[indexToMove];
});

console.log(arr);

Answer 3

Something like this?

// Array Remove - By John Resig (MIT Licensed)
Array.prototype.remove = function(from, to) {
  var rest = this.slice((to || from) + 1 || this.length);
  this.length = from < 0 ? this.length + from : from;
  return this.push.apply(this, rest);
};

var arr = [
{
    "id": "1",
    "dataId" : "", 
    "rel": []
}, 
{
    "id": "2",
    "dataId" : "", 
    "rel": []
}, 
{
    "id": "3", 
    "dataId" : "", 
    "rel": []   
}, 
{
    "id": "4",
    "dataId" : "1", 
    "rel": []   
}];

var index = 0;
for ( var m = 0; m < arr.length; m++ ) {
    for ( var i = 0; i < arr.length; i++ ) {

       if ( arr[index].id === arr[i].dataId ) {
             arr[index].rel.push (arr[i]);  
             arr.remove(i);
       }

    }
    index++;
}

console.log(JSON.stringify(arr, null, 4))