template dom-repeat does not iterate over array-like objects

[pmaudsley]

I know there is an issues regarding repeating over object keys in #1385

However, I am working with array-like objects and these also do not get stamped out either due to the Array.isArray() check.

I'll add a PR which implements a further check on objects passed through dom-repeat has the required properties and methods. (https://www.polymer-project.org/1.0/docs/devguide/properties#array-mutation)

[mattyclarkson]

To provide more background: We have a web API that we models objects as a sparse array:

{
  "elements": {
    "713": {
      "type": "abc"
    },
    "16": {
      "type": "foo"
    }
  }

These are represented as an array-like Object as so:

console.log(api.elements.length);  // => 2
console.log(api.elements[0]._id);  // => 713
console.log(api.elements[1]._id);  // => 16
api.elements.push({'type': 'foo'});
api.elements[2].loadId().then(console.log);  // => unique id (say, 199)
api.elements.splice(1, 1);  // Removes the object with ID 16 in the API and locally
console.log(api.elements[0]._id);  // => 713
console.log(api.elements[1]._id);  // => 199

For all intents an purposes, api.elements acts like and array. It implements all the functions that a ES2015 array implements and when objects are added/removed does the necessary grunt work to keep the API up-to-date. Representing the API as an array, makes Polymer integration easy as dom-repeat works really well in this situation, except...it doesn't work because it has a Array.isArray check that discards our object and doesn't create a collection from it.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed after being marked stale. If you're still facing this problem with the above solution, please comment and we'll reopen!