Add widget to consume BCN's timeline

[emibcn]

The idea is to add a widget:

• This is a Timeline data, which could match with a Timeline visualization like these ones, or some other (like Twitter/Facebook?). The original one is at Seguiment Covid19 BCN, section Cronograma/Timeline.
• Use react-window or similar to prevent mounting too much components
• Configurable tag list selector:
  • The tags may need to be manually/auto-post-processed grouped/structured (some are redundant, some may be included into others). Or look for another solution, like searching user inputs (including spaces) into each tag string.
  • The user may select multiple tags in a single widget
  • The widget shows a list of the messages matching the selected tags
  • Editable (saved) Positive/negative text filter? (in addition to tags selection/filter)
• Show some fast controls to the user, like:
  • Auto-scrolling on/off on date change
  • Zoom?
  • Positive/negative text filter?
• The widget will change depending on the currently selected date:
  • Center the visualization into the first message of the day
  • Animated scroll up/down on date change (controllable)

Data shape

BCN Timeline is a JSON containing an array similar to this:

[
  {
    date: "YYYY-MM-DD",
    title: "Some short text",
    tag: "Some non-cleaned up tag system",
  },
  ...
]

This data is scraped at Covid Data - BCN. There, some data post-processing may be added. For example, an index of {date: [matching messages]}, or some tags/grouping/fixing.

Original visualization

Data loading

It is loaded with the backend manager:

const cancelUpdates = this.BcnData.data('timeline', onLoadCallback);

Similar to BCN charts.

Some tags examples

• OMS declaracions emergència
• Internacional actuacions
• Govern d'Espanya Actuacions
• Primer cas a Espanya
• Cancel·lacions esdeveniments
• Primera mesura de confinament massiu
• Concentracions massives als carrers
• Espanya actuacions
  -...