tamtamchik / json-deep-sort

// Type definitions

type ObjectType = Record<string | symbol, unknown>;

type SortedEntry = [string | symbol, unknown];

type NonSortableType =

  | Date

  | RegExp

  | (() => unknown)

  | ((...args: unknown[]) => unknown)

  | Error

  | Map<unknown, unknown>

  | Set<unknown>

  | WeakMap<object, unknown>

  | WeakSet<object>

  | Promise<unknown>;

type SortOptions = {

  ascending: boolean;

  sortPrimitiveArrays: boolean;

};

// Main public API

export function sort<T>(

  data: T,

  ascending = true,

  sortPrimitiveArrays = false

): T {

  const options: SortOptions = { ascending, sortPrimitiveArrays };

  return sortRecursively(data, options);

}

// Core recursive sorting logic

function sortRecursively<T>(data: T, options: SortOptions): T {

  if (isPrimitive(data)) {

    return data;

  }

  if (Array.isArray(data)) {

    return sortArray(data, options) as T;

  }

  if (isObject(data) && !isNonSortableObject(data)) {

    return sortObject(data, options) as T;

  }

  return data;

}

// Array sorting logic

function sortArray<T>(array: T[], options: SortOptions): T[] {

  if (shouldSortPrimitiveArray(array, options.sortPrimitiveArrays)) {

    return sortPrimitiveArray(array, options.ascending) as T[];

  }

  return array.map((item) => sortRecursively(item, options));

}

// Object sorting logic

function sortObject(obj: ObjectType, options: SortOptions): ObjectType {

  const entries = collectObjectEntries(obj);

  const sortedEntries = sortObjectEntries(entries, options.ascending);

  return createSortedObject(sortedEntries, options);

}

// Primitive array sorting

function shouldSortPrimitiveArray(

  array: unknown[],

  sortPrimitiveArrays: boolean

): boolean {

  return (

    sortPrimitiveArrays && array.length > 0 && allItemsArePrimitives(array)

  );

}

function allItemsArePrimitives(array: unknown[]): boolean {

  return array.every((item) => isPrimitive(item));

}

function sortPrimitiveArray(array: unknown[], ascending: boolean): unknown[] {

  if (!allItemsHaveSameType(array)) {

    return array; // Mixed types maintain original order

  }

  return [...array].sort((a, b) => comparePrimitives(a, b, ascending));

}

function allItemsHaveSameType(array: unknown[]): boolean {

  if (array.length === 0) return true;

  const firstType = typeof array[0];

  return array.every((item) => typeof item === firstType);

}

function comparePrimitives(a: unknown, b: unknown, ascending: boolean): number {

  if (typeof a === 'string' && typeof b === 'string') {

    return ascending ? a.localeCompare(b) : b.localeCompare(a);

  }

  if (typeof a === 'number' && typeof b === 'number') {

    return compareNumbers(a, b, ascending);

  }

  if (typeof a === 'boolean' && typeof b === 'boolean') {

    return compareBooleans(a, b, ascending);

  }

  return 0; // Maintain order for other primitives

}

function compareNumbers(a: number, b: number, ascending: boolean): number {

  if (Number.isNaN(a) && Number.isNaN(b)) return 0;

  if (Number.isNaN(a)) return 1;

  if (Number.isNaN(b)) return -1;

  return ascending ? a - b : b - a;

}

function compareBooleans(a: boolean, b: boolean, ascending: boolean): number {

  if (a === b) return 0;

  if (a) return ascending ? 1 : -1;

  return ascending ? -1 : 1;

}

// Object entry handling

function collectObjectEntries(obj: ObjectType): SortedEntry[] {

  const stringEntries = Object.entries(obj);

  const symbolEntries = Object.getOwnPropertySymbols(obj).map(

    (symbol) => [symbol, obj[symbol]] as SortedEntry

  );

  return [...stringEntries, ...symbolEntries];

}

function sortObjectEntries(

  entries: SortedEntry[],

  ascending: boolean

): SortedEntry[] {

  return entries.sort(([keyA], [keyB]) =>

    compareObjectKeys(keyA, keyB, ascending)

  );

}

function compareObjectKeys(

  keyA: string | symbol,

  keyB: string | symbol,

  ascending: boolean

): number {

  if (typeof keyA === 'symbol' && typeof keyB === 'symbol') return 0;

  if (typeof keyA === 'symbol') return 1;

  if (typeof keyB === 'symbol') return -1;

  const stringA = keyA as string;

  const stringB = keyB as string;

  return ascending

    ? stringA.localeCompare(stringB)

    : stringB.localeCompare(stringA);

}

function createSortedObject(

  entries: SortedEntry[],

  options: SortOptions

): ObjectType {

  const sortedEntries = entries.map(([key, value]) => [

    key,

    sortRecursively(value, options),

  ]);

  return Object.fromEntries(sortedEntries);

}

// Type guards

function isPrimitive(data: unknown): boolean {

  return (

    data === null ||

    data === undefined ||

    typeof data === 'string' ||

    typeof data === 'number' ||

    typeof data === 'boolean'

  );

}

function isObject(data: unknown): data is ObjectType {

  return typeof data === 'object' && data !== null;

}

function isNonSortableObject(obj: unknown): obj is NonSortableType {

  const nonSortableTypes = [

    Date,

    RegExp,

    Function,

    Error,

    Map,

    Set,

    WeakMap,

    WeakSet,

    Promise,

  ];

  return (

    nonSortableTypes.some((type) => obj instanceof type) ||

    Symbol.iterator in Object(obj)

  );

}