How do I format currency in Vega-Lite?

Question

I'm trying to format values as currency in the Vega-Lite editor. I'm attempting to copy the docs but I'm getting a weird error. The Y axis is a numerical value. Passing in a formatting string gives "value expected".

Here's the relevant section:

...
    "encoding": {
        "x": {
            "axis": {
                "domainColor": "#DDD",
                "grid": false, 
                "labelColor": "#AEAEAE", 
                "ticks": false, 
                "labelPadding": 10
            }, 
            "field": "time", 
            "type": "temporal", 
            "title": ""
        },
        "y": {
            "axis": {
                "labelOffset": 2,
                "domainColor": "white",
                "labelColor": "#AEAEAE", 
                "ticks": false, 
                "labelPadding": 10,
                "format": '$.2f' // <- the line in question
            }, 
...

What am I missing here? How do I get it to accept my formatting string?

Answer 1

"$.2f" looks like a the correct d3-format string for currency, but note that this is only valid if the associated formatType is "number" (see axis label docs ).

Since you did not include a full reproducible example of the problem you're seeing, I can only venture a guess that your data type is not numeric, and this is why the formatting is failing. If that's not the case, I'd suggest editing your question to provide a complete example of the error you're seeing.