Query String Parser with Zod

qsZod.ts

import qs from "qs";
import { ZodSchema } from "zod";

const parseObjectPrimitives = (obj: Record<string, any>): any => {
  return Object.fromEntries(
    Object.entries(obj).map(([k, v]) => {
      if (typeof v === "object") return [k, parseObjectPrimitives(v)];
      if (!isNaN(parseFloat(v))) return [k, parseFloat(v)];
      if (v === "true") return [k, true];
      if (v === "false") return [k, false];
      if (typeof v === "string") return [k, v];
      return [k, null];
    })
  );
};

export const qsParse = <T>(queryString: string | Record<string, any>, schema: ZodSchema<T>) => {
  const parsed =
    typeof queryString === "string"
      ? qs.parse(queryString, {
          ignoreQueryPrefix: true
        })
      : queryString;

  const zResult = schema.safeParse(parseObjectPrimitives(parsed));

  return {
    data: zResult.success ? zResult.data : ({} as T),
    errors: !zResult.success
      ? zResult.error.issues.map(i => `${i.path.join(".")}: ${i.message}`).reduce((acc, v) => (acc.includes(v) ? acc : [...acc, v]), [] as string[])
      : []
  };
};

to not lose alphanumeric during parseFloat conversion, I add a number regex check:

/^[0-9]+$/i.test(v)

So the function parseObjectPrimitives:

const parseObjectPrimitives = (obj: Record<string, any>): any => {
  return Object.fromEntries(
    Object.entries(obj).map(([k, v]) => {
      if (typeof v === "object") return [k, parseObjectPrimitives(v)];
      if (/^[0-9]+$/i.test(v) && !isNaN(parseFloat(v))) return [k, parseFloat(v)]; // <== HERE
      if (v === "true") return [k, true];
      if (v === "false") return [k, false];
      if (typeof v === "string") return [k, v];
      return [k, null];
    })
  );
};

You can also parse neasted arrays:

function parseObjectPrimitives(obj: Record<string, any>): any {
  return Object.fromEntries(
    Object.entries(obj).map(([k, v]) => {
      if (Array.isArray(v)) return [k, v.map(parseObjectPrimitives)]; // <== HERE
      if (typeof v === "object") return [k, parseObjectPrimitives(v)];
      if (/^[0-9]+$/i.test(v) && !isNaN(parseFloat(v))) return [k, parseFloat(v)];
      if (v === "true") return [k, true];
      if (v === "false") return [k, false];
      if (typeof v === "string") return [k, v];
      return [k, null];
    })
  );
}