General JS/TS utility functions.

utils.ts

/***
 General utility functions by @DarkRoku12
***/

export async function batch_await_fn<T extends any[], R>( iArray: T, batchLen: number, fn: ( chunk: T ) => Promise<R | R[]> ) 
{
  const results = [] as R[];

  for ( let i = 0; i < iArray.length; i += batchLen ) 
  {
    const chunk = iArray.slice( i, i + batchLen ) as T;
    const checkResults = await fn( chunk );
    if ( Array.isArray( checkResults ) ) results.push( ...checkResults );
    else results.push( checkResults );
  }

  return results;
}

/** Convert an array<T> into chunks: array<T[]> */
export function in_chunks<T extends any[]>( iArray: T, chunkLen: number ) 
{
  const chunks = [] as T[];
  for ( let i = 0; i < iArray.length; i += chunkLen ) 
  {
    const chunk = iArray.slice( i, i + chunkLen ) as T;
    chunks.push( chunk );
  }
  return chunks;
}

export async function batch_await<T extends Promise<any>>( iArray: T[], batchLen: number ) 
{
  return batch_await_fn( iArray, batchLen, ( chunk ) => Promise.all( chunk ) );
}

export type STRIP_COMMON_PROPS = "password" | "created_at" | "updated_at" | "synced_at" | "deleted_at";

/** Strip common properties from an object. */
export function strip<T extends Record<any, any>, P extends Readonly<Array<keyof T>> = []>(
  obj: T,
  props?: P,
  defaults?: boolean,
): Omit<T, STRIP_COMMON_PROPS | P[number]> 
{
  const defProps = ["password", "created_at", "updated_at", "deleted_at", "synced_at"] as const;
  const delProps = [...( defaults ? defProps : [] ), ...( props || [] )];

  for ( const prop of delProps ) delete obj[prop];
  return obj as Omit<T, STRIP_COMMON_PROPS | P[number]>;
}

/** Strip common properties from an object (copy). */
export function copy_strip( obj: Record<any, any> ) 
{
  return strip( { ...obj } );
}

/** Pick properties from an object. */
export function pick<T extends Record<any, any>, P extends Readonly<Array<keyof T>> = []>( obj: T, props: P ): Pick<T, P[number]> 
{
  const newObj = {} as Pick<T, P[number]>;
  for ( const prop of props ) newObj[prop] = obj[prop];
  return newObj;
}

/** Make an array unique (copy). */
export function unique<T>( array: T[] ) 
{
  return [...new Set( array )];
}