How to push to an array?

I have a text array column, not nullable, and am having trouble pushing to the array in PG

await db
  .update(table1)
  .set({
    textArrayField: sql`${table1.textArrayField} || 'someString`
  })
  .where(eq(table1.id, someId));

await db
  .update(table1)
  .set({
    textArrayField: sql`${table1.textArrayField} || 'someString`
  })
  .where(eq(table1.id, someId));

await db
  .update(table1)
  .set({
    textArrayField: sql`${table1.textArrayField} || 'someString`
  })
  .where(eq(table1.id, someId));

await db
  .update(table1)
  .set({
    textArrayField: sql`${table1.textArrayField} || 'someString`
  })
  .where(eq(table1.id, someId));

and i get a very unhelpful error:

TypeError: value.map is not a function