@jacobmarshall/kv/kv.js

A super simple key value store backed by IndexedDB

(function() {
  'use strict';

  var DB_NAME = 'kv';
  var STORE_NAME = 'kv';
  var TRANS_RO = 'readonly';
  var TRANS_RW = 'readwrite';

  function kv(name) {
    var db;

    function getDB() {
      if (!db) {
        db = new Promise(function(resolve, reject) {
          var openreq = indexedDB.open(name, 1);
          openreq.onerror = function() {
            reject(openreq.error);
          };
          openreq.onupgradeneeded = function() {
            // First time setup: create an empty object store
            openreq.result.createObjectStore(STORE_NAME);
          };
          openreq.onsuccess = function() {
            resolve(openreq.result);
          };
        });
      }
      return db;
    }

    function withStore(type, callback) {
      return getDB().then(function(db) {
        return new Promise(function(resolve, reject) {
          var transaction = db.transaction(STORE_NAME, type);
          transaction.oncomplete = function() {
            resolve();
          };
          transaction.onerror = function() {
            reject(transaction.error);
          };
          callback(transaction.objectStore(STORE_NAME));
        });
      });
    }

    return {
      get: function(key) {
        var req;
        return withStore(TRANS_RO, function(store) {
          req = store.get(key);
        }).then(function() {
          return req.result;
        });
      },
      set: function(key, value) {
        return withStore(TRANS_RW, function(store) {
          store.put(value, key);
        });
      },
      remove: function(key) {
        return withStore(TRANS_RW, function(store) {
          store.delete(key);
        });
      },
      clear: function() {
        return withStore(TRANS_RW, function(store) {
          store.clear();
        });
      },
      keys: function() {
        var keys = [];
        return withStore(TRANS_RO, function(store) {
          // This would be store.getAllKeys(), but it isn't supported by Edge or Safari.
          // And openKeyCursor isn't supported by Safari.
          (store.openKeyCursor || store.openCursor).call(store).onsuccess = function() {
            if (!this.result) return;
            keys.push(this.result.key);
            this.result.continue();
          };
        }).then(function() {
          return keys;
        });
      }
    };
  }

  var def = kv(DB_NAME);
  for (var name in def) {
    if (def.hasOwnProperty(name)) {
      kv[name] = def[name];
    }
  }

  if (typeof module != 'undefined' && module.exports) {
    module.exports = kv;
  } else if (typeof define === 'function' && define.amd) {
    define('kv', [], function() {
      return kv;
    });
  } else {
    self.kv = kv;
  }
})();