share/sharedb

Projection's nested fields aren't being updated when subscribing to a query

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#365 opened on Apr 21, 2020

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 (1 comment) (0 reactions) (0 assignees)JavaScript (449 forks)batch import
enhancementhelp wanted

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Description

Created a projection as follows:

  backend.addProjection 'gameInfos', 'games',
    id: true
    testGame: true
    host: true
    classIds: true
    createdAt: true    
    mode: true
    'scenario.name': true
    'scenario.labels.publish': true
    'scenario.labels.unpublish': true
    'scenario.scenarioName': true
    'scenario.playedAt': true
    'scenario.gameCategory': true
    'scenario.gameType': true
    'scenario.password': true
    'scenario.roles': true

Subscribed to a regular query:

   $games = @model.query 'gameInfos', someQuery
   @model.subscribe $games, =>
       @model.ref '_page.games', $games
       @page.render ...

All first-level nested fields, e.g. mode, host are being reactively updated. But the specified nested fields, e.g. scenario.name are not. It will work fine if I pass just scenario: true into addProjection, i.e. all nested fields under scenario object will be updated reactively, but what if I only want a subset of the nested fields.

Contributor guide

Research direction
Investigate the projection handling logic in ShareDB to see how nested fields are subscribed and updated. Focus on the subscribe method and how projections are applied to query results. Look for any filtering that might skip nested fields.
Tech stack
javascript
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60