combine js array's

pretty simple question, can't quite fig. it out.

I have 2 js array's that I need to combine into a new array, based on sub_key.

var items = [
     Object { 
         OBJECTID=1,
         Name="COMMAND B", 
         ID="AR0xx",
         sub_key="1000"
         },
     Object {
         OBJECTID=2, 
         Name="95TH PCT", 
         ID="AR0xx",
         sub_key="1001"
         },
    Object { 
         OBJECTID=379, 
         Name="dummy4", 
         ID="AR0xx",
         sub_key="9999"
         }
    ];
 
 var subitems = [
    Object { 
        OBJECTID=787, 
        ID="AR0xx", 
        sub_key=1000, 
        Long_Name = foo
        }, 
    Object { 
        OBJECTID=789, 
        ID="AR0xx", 
        sub_key=1001, 
        Long_Name = "bar"
        }, 
    Object { 
        OBJECTID=1, 
        ID="AR0xx", 
        sub_key=1001, 
        Long_Name="baz"
        }, 
    Object { 
        OBJECTID=788,
        ID="AR0xx", 
        sub_key=1001,
        Long_Name="buzzz"
        }
    ];
 

I'd like to create an array like so, which just combines the above 2, based on sub_key

var data = [
     COMMAND B=["foo"],
     95TH PCT=["bar","baz","buzz"]
     dummy4=[]
     ];
 

Here's what I tried but it doesn't work... i think i'm close?? thanks for any help!

data = [];
 for (var key in items){
     var o = items[key];
     //data.push(o.Name);
     for (var subkey in subitems){
         subo = subitems[subkey];
         if (o.sub_key == subo.sub_key){
             data[o.Name].push(subo.Long_Name)
         }
     }
 }
 

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