typia/src/functional/$QueryReader/$QueryReader.ts

Superfast runtime validators with only one line

export const boolean = (str: string | null): boolean | null | undefined =>
  str === null
    ? undefined
    : str === "null"
      ? null
      : str.length === 0
        ? true
        : str === "true" || str === "1"
          ? true
          : str === "false" || str === "0"
            ? false
            : (str as any); // wrong type

export const number = (str: string | null): number | null | undefined =>
  !!str?.length ? (str === "null" ? null : (toNumber(str) as any)) : undefined;

export const bigint = (str: string | null): bigint | null | undefined =>
  !!str?.length ? (str === "null" ? null : (toBigint(str) as any)) : undefined;

export const string = (str: string | null): string | null | undefined =>
  str === null ? undefined : str === "null" ? null : str;

export const params = (input: string | URLSearchParams) => {
  if (typeof input === "string") {
    const index: number = input.indexOf("?");
    input = index === -1 ? "" : input.substring(index + 1);
    return new URLSearchParams(input);
  }
  return input;
};

export const array = (input: any[], alternative: null | undefined) =>
  input.length ? input : alternative;

const toNumber = (str: string): number | string => {
  const value: number = Number(str);
  return isNaN(value) ? str : value;
};

const toBigint = (str: string): bigint | string => {
  try {
    return BigInt(str);
  } catch {
    return str;
  }
};