Strata · Migrations

Marker migrations

A migration with steps: [] is a marker: it increments the grammar’s version without transforming any document. Use it to record an addition to a strict grammar. Code that has the marker reads an older document unchanged, and code from before it rejects a document stamped after it with TOO_NEW, where it would otherwise have met an unknown key.

Migration 2 (marker)

{ description: 'A button may carry an icon', steps: [] }

Stored document

{ text: 'Book seats' }

Stored stamp

{ theatre.buttons: 1 }

Output

{
  document: { text: 'Book seats' },
  stamp: { theatre.buttons: 2 },
  applied: ['theatre.buttons/2'],
}

Output matches the expected value

Runs in this page on the installed package. The input and the expected output are defined by the example.