Implementing a word ladder solution in JavaScript can be quite complex as it requires constructing a graph of all possible word transformations and then performing a breadth-first search (BFS) to find the shortest path from the start word to the end word. This would also require a dictionary of five-letter words, which is too large to easily include in this context.

Here's a simplified and unoptimized example of how such a function might look like:

function findWordLadder(start, end, dict) { let queue = [[start]]; let visited = new Set([start]); while (queue.length > 0) { let path = queue.shift(); let word = path[path.length - 1]; if (word === end) { return path; } for (let i = 0; i < word.length; i++) { for (let j = 0; j < 26; j++) { let newWord = word.slice(0, i) + String.fromCharCode(97 + j) + word.slice(i + 1); if (!visited.has(newWord) && dict.has(newWord)) { queue.push([...path, newWord]); visited.add(newWord); } } } } return null; } let startWord = 'reach'; let endWord = 'grasp'; let dictionary = new Set(['reach', 'peach', 'peace', 'place', 'plage', 'pages', 'pases', 'pares', 'parse', 'grasp']); console.log(findWordLadder(startWord, endWord, dictionary));

This function operates by maintaining a queue of word paths and iteratively expanding each path until it reaches the end word. Please note that the performance of this function can be substantially affected by the size of the dictionary it's given.

Remember to adjust the dictionary to include all the five-letter words you need, as well as to take into account the computational resources and time required for the function to execute, especially for large dictionaries.