Given an array of strings, group anagrams together in Javascript

findAnagramGroups.ts

/**
 * This problem was asked by Robinhood.

 Given an array of strings, group anagrams together.

 For example, given the following array:

 ['eat', 'ate', 'apt', 'pat', 'tea', 'now']
 Return:

 [['eat', 'ate', 'tea'],
 ['apt', 'pat'],
 ['now']]

 TimeComplexity: o(n^2)
 */

export function findAnagramGroups<Input extends Array<string>>(list: Input): Array<Input> {
    const anagramsDictionary: Array<Input> = [];
    const processed: Record<string, boolean> = {}

    for (let i = 0; i < list.length; i++) {
        const wordI = list[i];

        for (let j = i + 1; j < list.length; j++) {
            const wordJ = list[j];
            if(isAnagram(wordI, wordJ)) {
                if(anagramsDictionary[i] && !anagramsDictionary[j]) {
                    anagramsDictionary[i].push(wordJ);
                }else {
                    if(!processed.hasOwnProperty(wordJ)) {
                        anagramsDictionary[i] = [wordI, wordJ] as Input;
                    }
                }
                processed[wordI] = true;
                processed[wordJ] = true;
            }
        }

        if(!processed[wordI]) {
            anagramsDictionary[i] = [wordI] as Input;
        }
    }

    return anagramsDictionary.filter(Boolean);
}

function isAnagram(str1: string, str2: string): boolean {
    return sortAndClean(str1) === sortAndClean(str2);
}
function sortAndClean(str: string): string {
  return str.replace(/[^\w]/g, '').toLowerCase().split('').sort().join('');
}