Function createMockTx

packages/dotcom-shared/src/mutators.test.ts:151–281

* Build a mock Transaction that resolves zql builder queries against in-memory data. * * The `tx.run(query)` API passes an AST, but the builder stores filter info. * We intercept via Proxy so `.where()` chains build up predicates, and * `.one()` / the final run resolves them. * * This is a sim

(
	store: TableStore,
	opts: { location: 'server' | 'client' } = { location: 'server' }
)

 *   zql.<table>.where(col, '=', val)
 */
function createMockTx(
	store: TableStore,
	opts: { location: 'server' | 'client' } = { location: 'server' }
) {
	// Track mutations for assertions
	const mutations: Array<{ op: string; table: string; data: any }> = []

	function getRows(table: keyof TableStore) {
		return store[table] ?? []
	}

	function matchPk(table: keyof TableStore, row: any, data: any) {
		return TABLE_PKS[table].every((pk) => row[pk] === data[pk])
	}

	// The mutate object provides insert/update/upsert/delete for each table
	function makeTableMutator(tableName: keyof TableStore) {
		return {
			insert: async (data: any) => {
				mutations.push({ op: 'insert', table: tableName, data })
				;(store[tableName] as any[]).push({ ...data })
			},
			update: async (data: any) => {
				mutations.push({ op: 'update', table: tableName, data })
				const rows = store[tableName] as any[]
				const idx = rows.findIndex((r) => matchPk(tableName, r, data))
				if (idx >= 0) Object.assign(rows[idx], data)
			},
			upsert: async (data: any) => {
				mutations.push({ op: 'upsert', table: tableName, data })
				const rows = store[tableName] as any[]
				const idx = rows.findIndex((r) => matchPk(tableName, r, data))
				if (idx >= 0) {
					Object.assign(rows[idx], data)
				} else {
					rows.push({ ...data })
				}
			},
			delete: async (data: any) => {
				mutations.push({ op: 'delete', table: tableName, data })
				const rows = store[tableName] as any[]
				const idx = rows.findIndex((r) => matchPk(tableName, r, data))
				if (idx >= 0) rows.splice(idx, 1)
			},
		}
	}

	const mutate: any = {}
	for (const t of Object.keys(store) as (keyof TableStore)[]) {
		mutate[t] = makeTableMutator(t)
	}

	// tx.run(query) — the query is a builder that carries an AST.
	// We need to resolve it against our store.
	// The builder from createBuilder(schema) returns objects with .ast property.
	// We parse the AST to figure out which table + where clauses + one().
	function resolveAst(ast: any): any[] {
		const table = ast.table as keyof TableStore