[Offirmo's migrations] #Offirmo #TypeScript

migrations.ts

import { enforce_immutability, LastMigrationStep, MigrationStep, generic_migrate_to_latest } from '@offirmo-private/state-utils'

import { LIB, SCHEMA_VERSION } from './consts'
import { UState, TState } from './types'
import { OMRSoftExecutionContext } from './sec'

// some hints may be needed to migrate to demo state
// need to export them for composing tests
export const MIGRATION_HINTS_FOR_TESTS: any = enforce_immutability({
})

/////////////////////


/////////////////////

type StateForMigration = [UState, TState]

export function migrate_to_latest(SEC: OMRSoftExecutionContext, legacy_state: Readonly<any>, hints: Readonly<any> = {}): StateForMigration {
	return generic_migrate_to_latest({
		SEC: SEC as any,
		LIB,
		SCHEMA_VERSION,
		legacy_state,
		hints,
		sub_states_migrate_to_latest: {},
		pipeline: [
			migrate_to_4x,
			migrate_to_3,
			migrate_to_2,
		]
	})
}

/////////////////////

const migrate_to_4x: LastMigrationStep<StateForMigration, [any, any]> = (SEC, legacy_state, hints, previous, legacy_schema_version) => {
	//console.log('hello from migrate_to_4x', legacy_state, hints, previous, legacy_schema_version)
	if (legacy_schema_version < 3)
		legacy_state = previous(SEC, legacy_state, hints)

	let [ u_state, t_state ] = legacy_state
	u_state = {
		...u_state,
		schema_version: 4,
	}
	t_state = {
		...t_state,
		schema_version: 4,

		// this field was added
		revision: u_state.revision,
	}
                                       
    // eventually, update schema version
    state.schema_version = 14
	state.t_state.schema_version = 14
	state.u_state.schema_version = 14
	state = {
		...state,
		u_state: {
			...state.u_state,
			schema_version: 15,
		},
		t_state: {
			...state.t_state,
			schema_version: 15,
		},
	}

	return [ u_state, t_state ]
}

const migrate_to_3: MigrationStep<[any, any], [any, any]> = (SEC, legacy_state, hints, next, legacy_schema_version) => {
	if (legacy_schema_version < 2)
		legacy_state = next(SEC, legacy_state, hints)

	let state: any = {
		...legacy_state,
		slot_id: 0,
	}
	delete state.persistence_id

	return state
}
                                       
const migrate_to_2: MigrationStep<[any, any], [any, any]> = () => {
	throw new Error('Schema is too old (pre-beta), can’t migrate!')
}