• I'm submitting a Bug

• bug report
• feature request
• support / question

Brief Description

Loading of some changesets fails.

What is the current behaviour, (attach relevant screenshots) ?

TypeError: Cannot read property 'toString' of null

What is the expected behaviour ?

A better error message or maybe no error at all.

When does this occur ?

When the changeset has no closed_at property.

How do we replicate the issue ?

Example changeset: https://www.openstreetmap.org/api/0.6/changeset/109618303.json?include_discussion=true

Other Information / context:

c.to can be null

Possible solutions:

1. Better error message

var data = getDataParam(changeset);
+ if (!data.to) {
+   new Error('Changeset has no closed_at property!')
+ }

2. Not returning null.

- to: cs.closed_at || null,
+ to: cs.closed_at || …,