include `formatLocale` and `timeFormatLocale` parameters in options

Reasoning: I would like to set the formatLocale and formatTimeLocale as part of the embed_options in Altair.

At the vega repo, @jheer did comment once that you will need to invoke the formatLocale and formatTimeLocale methods prior instantiation of a Vega View (https://github.com/vega/vega/pull/313#issuecomment-297562302).

Using this approach I can set it in VegaEmbed: https://observablehq.com/@mattijn/usage-of-timeformatlocale-formatlocale-in-vega-embed, but this is prior the invokation of the View constructor.

Basically its just:

embed = require("vega-embed@4")
formatlocale = await (await fetch("https://unpkg.com/d3-format@1/locale/nl-NL.json")).json()
timeformatlocale = await (await fetch("https://unpkg.com/d3-time-format@1/locale/nl-NL.json")).json()
embed.vega.timeFormatLocale(timeformatlocale)
embed.vega.formatLocale(formatlocale)

viewof view = embed({
  "$schema": "https://vega.github.io/schema/vega-lite/v3.json",
  "description": "Google's stock price over time.",
  "width": 700,
  "data": {"url": "https://raw.githubusercontent.com/vega/vega-datasets/master/data/stocks.csv"},
  "transform": [{"filter": "datum.symbol==='GOOG'"}],
  "mark": {
    "type": "area",
    "color": "lightblue",
    "interpolate": "step-after",
    "line": true
  },
  "encoding": {
    "x": {"field": "date", "type": "temporal"},
    "y": {"field": "price", "type": "quantitative"},
    "tooltip": [
      {"type": "quantitative", "field": "price", "format": "$,"},
      {"type": "temporal", "field": "date"}
    ],
  },
  "selection": {
    "zoom_x": {"type": "interval", "bind": "scales", "encodings": ["x"]}
  },
})

Would it be possible to provide these locale settings as options in the Vega-Embed View?

Other sources of similar requests for Altair:

• https://vega-js.slack.com/archives/C7K00SK98/p1560523113006600
• https://github.com/altair-viz/altair/issues/505

[domoritz]

Fixed and released in 6.1.0.

[victornoel]

@domoritz maybe just delegate the responsibility of handling this to vega itself by considering the following reasoning:

• vega exposes methods to change its instance locales
• vega-embed just uses those methods, and don’t “know” that actually d3 is globally scoped

It’s a bit cheating instead of dealing with the problem, but at the same time, think that where this problem can be fixed is at the level of vega itself when it uses d3.