LocalStorage Size from https://raw.githubusercontent.com/bahmutov/code-snippets/master/local-storage-size.js

localstorage-size.js

// CM: forked to address key size (not just value size), swapping between KB and MB, ordering by size and logging total localstorage size.
// based on answer to question
// http://stackoverflow.com/questions/4391575/how-to-find-the-size-of-localstorage
(function showLocalStorageSize() {

  threshold = 256; // the point where we stop displaying KB and start with MB
  
  function stringSizeBytes(str) {
    return str.length * 2;
  }

  function toMB(bytes) {
    return bytes / 1024 / 1024 ;
  }

  function toKB(bytes) {
    return bytes / 1024 ;
  }

  function toSize(key) {
    return {
      name: key,
      size: stringSizeBytes(localStorage[key]) + stringSizeBytes(key)
    };
  }

  function toSizeKBMB(info) {
    if (info.size > (threshold * 1024)) {
       info.size = toSizeMB(info.size);
    } else {
       info.size = toSizeKB(info.size);
    }
    return info;
  }

  function toSizeKB(size) {
    return toKB(size).toFixed(2) + ' KB';
    return info;
  }

  function toSizeMB(size) {
    return toMB(size).toFixed(2) + ' MB';
  }

  // LOG SIZE BY KEY
  var keysArray = Object.keys(localStorage);
  var sizes = keysArray.map(toSize);
  sizes.sort(function(a,b) {
    return a.size - b.size;
  }).reverse();
  sizes.map(toSizeKBMB);
  console.table(sizes);

  // LOG TOTAL SIZE
  var total = 0;
  keysArray.map(function(key) {
    total += toSize(key).size;
  });
  total = (total > (threshold * 1024) ? toSizeMB(total) : toSizeKB(total) );
  console.warn('TOTAL LOCALSTORAGE SIZE: ' + total);

}());