CODEWITHSUNDEEP
javascriptarraysobject
PatriciaW
PatriciaW

Reputation: 913

Javascript - Undefined attribute in array of objects

I am attempting to add two attributes to a array of objects so I decided to create a new array of objects from the original one and then set the new attributes. (I realize there are probably be easier ways of doing this.)

My problem is that when I attempt to access an attribute within the new array it is undefined. What is wrong is probably obvious but not to me. Help!

var join = [];
for (linksIndex = 0; linksIndex < links.length; ++linksIndex) {
     join.push([{source:links[linksIndex].source,target:links[linksIndex].target, x1:0, y1:0, x2:0, y2:0}]);
    };

for (joinIndex = 0; joinIndex < join.length; ++joinIndex) {

//   console.log("join in loop");console.log(join); // ok array of objects
//   console.log("join[joinIndex]");console.log(join[joinIndex]); // on object
   console.log("join[joinIndex].source");console.log(join[joinIndex].source); // undefined why?

   for (nodesIndex = 0; nodesIndex < nodes.length; ++nodesIndex) {
      if (nodes[nodesIndex].name == join[joinIndex].source) { 
        join[joinIndex].x1=nodes[nodesIndex].x; // match source 
        join[joinIndex].y1=nodes[nodesIndex].y; // match source
        };  
     if (nodes[nodesIndex].name == join[joinIndex].target) { 
        join[joinIndex].x2=nodes[nodesIndex].x; // match target
        join[joinIndex].y2=nodes[nodesIndex].y; // match target
        } ;   
   }
 }

Upvotes: 0

Views: 269

Answers (3)

Kai
Kai

Reputation: 1225

You are pushing in the array another array with an object!

so if you change it to:

join[joinIndex][0].source

it will work. But i guess this is not what you want. So change the join.push() to:

join.push({
    source: links[linksIndex].source,
    target: links[linksIndex].target,
    x1: 0,
    y1: 0,
    x2: 0,
    y2: 0
});

Upvotes: 0

acjay
acjay

Reputation: 36521

You're pushing arrays containing objects into your join array. When you attempt to access x1 or x2 in the array, you're getting undefined, because the array only has one element at 0 (which is the object you're expecting).

You need to do: join.push({source:links[linksIndex].source,target:links[linksIndex].target, x1:0, y1:0, x2:0, y2:0})

It would be easy to catch this error by using a debugger. I would put a breakpoint on the second loop, and it would be easy to see exactly what join contains.

Upvotes: 0

juvian
juvian

Reputation: 16068

Change this:

     join.push([{source:links[linksIndex].source,target:links[linksIndex].target, x1:0, y1:0, x2:0, y2:0}]);

To:

     join.push({source:links[linksIndex].source,target:links[linksIndex].target, x1:0, y1:0, x2:0, y2:0});

Or use console.log(join[joinIndex][0].source);//you need to access the array you made

Upvotes: 1

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