simple HashTable example

hashTableWithRemove.js

// This is an example of a simplified javascript hash table that showcases a neat way (ln 64) to remove entries without 
// unneccesary iteration and without leaving undefined values lying around.

// I was too lazy to write a real hashing function, so just pretend that the hash function shown at the bottom works perfectly

var makeHashTable = function(){
  var result = {};
  result.storage = [];
  var storageLimit = 10;

  result.insert = function(key, value){
    var i = getIndexBelowMaxForKey(key, storageLimit);

    // If no bucket, make one
    if (!result.storage[i]){
      var bucket = [];
      bucket.push([key, value]);
      result.storage[i] = bucket;
    } else {

      var length = result.storage[i].length;

      // Loop through all items in the bucket, checking for matching keys
      for (var j = 0; j < length; j++) {

        // If the key is already present, overwrite the value
        if (result.storage[i][j][0] === key){
          result.storage[i][j][1] = value;
        } else {
          // else, push in a new tuple containing key:value pair
          result.storage[i].push([key, value]);
        }
      }
    }
  };

  result.retrieve = function(targetKey){
    var i = getIndexBelowMaxForKey(targetKey, storageLimit);

    var bucket = result.storage[i] || [];
    // Loop through bucket and look for matching key
    for (var j = 0; j < bucket.length; j++){
      // If key is found, return the corresponding value
      if (bucket[j][0] === targetKey) {
        return bucket[j][1];
      }
    }
  };

  result.remove = function(targetKey){
    var i = getIndexBelowMaxForKey(targetKey, storageLimit);

    var bucket = result.storage[i] || [];
    // Loop though bucket looking for matching key
    for (var j = 0; j < bucket.length; j++){

      // If key is found ...
      if (bucket[j][0] === targetKey) {
        // If the bucket has only one item, empty it completely
        if (bucket.length <= 1){
          result.storage[i] = [];
        } else {
          // else, replace the unwanted key:value pair with the popped-off last pair in the bucket
          result.storage[i][j] = bucket.pop();
        }
      }
    }
  };

  return result;
};

var getIndexBelowMaxForKey = function(str, max){
  // Returns an index below the max. This index will return the same for any given key every time it is called.
};