system-cache.js

system.cache.js

var each = function(arr, cb){
  var i = 0, len = arr.length;
  for(; i < len; i++) {
    if(cb(arr[i]) === false) {
      return;
    }
  }
};

var baseImport = System.import;
System.import = function(){
  var loader = this, args = arguments;
  return cached.then(function() {
    return baseImport.apply(loader, args);
  }).then(function(mod) {
    merge();
    return mod;
  });
};

var sources = {};

var fetch = System.fetch;
System.fetch = function(load) {
  return fetch.call(this, load).then(function(source) {
    if(/node_modules/.test(load.address)) {
      sources[load.name] = source;
    }
    return source;
  });
};

function merge(mod) {
  return get("modules").then(function(mods) {
    mods = mods || {};
    for (var p in sources) {
      mods[p] = sources[p];
    }
    return set("modules", mods);
  });
}

function get(key) {
  return getDb().then(function(db){
    return new Promise(function(resolve, reject) {
      var tx = db.transaction([OS_NAME], "readonly");
      var req = tx.objectStore(OS_NAME).get(key);
      req.onerror = reject;
      req.onsuccess = function(e){
        resolve(e.target.result);
      };
    });
  });
}

function set(key, value) {
  return getDb().then(function(db) {
    return new Promise(function(resolve, reject) {
      var tx = db.transaction([OS_NAME], "readwrite");
      var req = tx.objectStore(OS_NAME).put(value, key);
      req.onerror = reject;
      req.onsuccess = function(e){
        resolve(value);
      };
    });
  });
}

var DB_NAME = System.cachedb ||  "__system-cache";
var OS_NAME = "sources";

var getDb = (function(){
  var db;
  return function(){
    if(db) return Promise.resolve(db);

    return new Promise(function(resolve, reject) {
      var req = indexedDB.open(DB_NAME, 1);
      req.onerror = reject;
      req.onsuccess = function(e){
        db = e.target.result;
        resolve(db);
      };
      req.onupgradeneeded = function(e){
        var db = e.target.result;
        if(!db.objectStoreNames.contains(OS_NAME)) {
          db.createObjectStore(OS_NAME);
        }
      };
    });
  };
})();

var cached = get("modules").then(function(mods) {
  for(var name in mods) {
    System.define(name, mods[name]);
  }
});

System.cacheClean = function() {
  return new Promise(function(resolve, reject) {
    var req = indexedDB.deleteDatabase(DB_NAME);
    req.onsuccess = resolve;
    req.onerror = reject;
  });
};