Parts can be added to the design add build time, by passing them to the Design constructor, or at runtime by calling Pattern.addPart(). The latter approach is rarely used, but it’s there if you need it.
At build time
mjs
import { Design } from '@freesewing/core'
import { myPart } from './mypart.mjs'
const Sorcha = new Design({
parts: [ myPart ]
})
At run time
mjs
import { Aaron } from '@freesewing/aaron'
import { myRuntimePart } from './mypart.mjs'
const pattern = new Aaron()
pattern.addPart(myRuntimePart)