openai/src/_vendor/zod-to-json-schema/parsers/nativeEnum.ts

The official TypeScript library for the OpenAI API

import { ZodNativeEnumDef } from 'zod';

export type JsonSchema7NativeEnumType = {
  type: 'string' | 'number' | ['string', 'number'];
  enum: (string | number)[];
};

export function parseNativeEnumDef(def: ZodNativeEnumDef): JsonSchema7NativeEnumType {
  const object = def.values;
  const actualKeys = Object.keys(def.values).filter((key: string) => {
    return typeof object[object[key]!] !== 'number';
  });

  const actualValues = actualKeys.map((key: string) => object[key]!);

  const parsedTypes = Array.from(new Set(actualValues.map((values: string | number) => typeof values)));

  return {
    type:
      parsedTypes.length === 1 ?
        parsedTypes[0] === 'string' ?
          'string'
        : 'number'
      : ['string', 'number'],
    enum: actualValues,
  };
}