Non-contiguous time series in Highcharts

Non-contiguous time series in Highcharts

I would like to create a zoomable time series chart of the number of
Tweets that an an account posted per day. My server returns data for the
dates where Tweets occurred, that looks like this:
[
"2009-01-12",
3
], [
"2009-01-15",
1
], [
"2009-01-16",
1
], [
"2009-01-30",
2
]
I know that the ISO 8601 date can be converted with Date.parsedate(). Can
I register it as a callback to convert the dates? How can I create a
zoomable chart with irrigular intervals?