I'd like to show the difference between a date (Date1) from my data and "today" in my chart. I could add a column in my table that contains today's date, but I was wondering if I can somehow solve this in the transform [] statement to keep my tables lean.
Does something like:
today()
exist in vega-lite?
You can use the now() function within the vega-expression; see https://vega.github.io/vega/docs/expressions/#now
Here's a simple example of adding a column with today's date (open in editor):
{
"data": {
"values": [
{"date": "2020-01-01T00:00:00"},
{"date": "2021-01-01T00:00:00"},
{"date": "2021-02-01T00:00:00"}
]
},
"transform": [{"calculate": "now()", "as": "today"}],
"mark": "point",
"encoding": {
"x": {"field": "today", "timeUnit": "yearmonthdate", "type": "ordinal"},
"y": {"field": "date", "timeUnit": "yearmonthdate", "type": "ordinal"}
}
}
