JS ngram + ngram mash

ngram_plus_ngram_mash.js

function ngram(string)
{
  string = string.toString().toLowerCase();
	var valid = 'abcdefghijklmnopqrstuvwxyz '; for(var s = 0; s < string.length; s++) if(valid.indexOf(string[s]) == -1) { string = string.slice(0, s) + string.slice(s + 1); s--; }
	string = string.split(' ');
	var ngrams = [];
	var to_gram = ngram_mash(string);
	to_gram.push(string);
	for(var g = 0; g < to_gram.length; g++)
	{
		for(var l = 0; l < to_gram[g].length; l++)
		{
			for(var r = l; r < to_gram[g].length; r++)
			{
				var ngram = to_gram[g][l];
				for(var lr = l + 1; lr <= r; lr++) ngram += ' ' + to_gram[g][lr];
				if(ngrams.indexOf(ngram) == -1) ngrams.push(ngram);
			}
		}
	}
	console.log(ngrams);
}
function ngram_mash(split_string)
{
	var done = [];
	var todo = [];
	todo.push(split_string);
	while(todo.length > 0)
	{
		var current  = todo[0]; todo.splice(0, 1);
		for(var m = 0; m < current.length - 1; m++)
		{ 
			var building = [];
			for(var c = 0; c < current.length; c++)
			{
				if(m == c) { building.push(current[c] + current[c + 1]); c++; }
				else building.push(current[c]);
			}
			if(todo.indexOf(building) == -1) todo.push(building);
		}
		if(done.indexOf(current) == -1) done.push(current);
	}
	return done;
}