Description

Description:

Adds {$replaceWith: "$expression"} as an alias for {$replaceRoot: {newRoot: "$expression"}}.

*note* from cr for $set, the various accumulators available in stages other than $group ( also include $expr and more generally wherever expressions are supported)*

Engineering Ticket Description:

Add $replaceWith as a shortcut for {$replaceRoot: {newRoot: expression}}.

Scope of changes

• redirects
• 4.2 rel notes
• new replaceWith page
• Link to/for replaceRoot
• agg toc pages
• changestreams
• 4.2-downgrades (since either before/after, should remove from view definitions)
• accumulators

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)