cli-legend/RogueMaze/node_modules/rxjs/src/internal/util/not.ts

"A fun command-line rogurelike dungeon game"

export function not<T>(pred: (value: T, index: number) => boolean, thisArg: any): (value: T, index: number) => boolean {
  return (value: T, index: number) => !pred.call(thisArg, value, index); 
}