Function compileSingleRowRef

packages/db/src/query/compiler/evaluators.ts:216–230

* Compiles a reference expression for single-row evaluation

(ref: PropRef)

 * Compiles a reference expression for single-row evaluation
 */
function compileSingleRowRef(ref: PropRef): CompiledSingleRowExpression {
  const propertyPath = ref.path

  // This function works for all path lengths including empty path
  return (item) => {
    let value: any = item
    for (const prop of propertyPath) {
      if (value == null) {
        return value
      }
      value = value[prop]
    }
    return value
  }
}

/**
 * Compiles a function expression for both namespaced and single-row evaluation