cache-stack

Utility that caches functions (until they expire) and stacks callbacks (for longer running functions).

npm install cache-stack

Usage

var cacheStack = require('cache-stack');

var cs = cacheStack(
  // db call, or some other longer running operation
  function(onResult) {
    Transaction.find({
      user: <MongoId>
    }).lean().exec(onResult);
  },

  { // everything, including this object, is optional
    key: 'unique-id-1234', // by default, cacheStack will try to create a key
                           // for the data based on the first argument.
                           // if you don't expect that to be unique, then pass
                           // a unique key here.
    expires: '+1 hour', // default is +1 minute
                        // milliseconds, seconds, minutes, hours, days, months, years
    debug: true, // outputs some console logs so that you can see what's happening.
                 // default is false
    useCache: true // set to false if you want a new execution of the function.
                   // default is true
  },

  function() {
    // do something when the function returns data
  }
);

// cs.clear(); to clear the cache immediately.

Example

See this running on tonicdev here: https://tonicdev.com/jimmybyrum/57318ea5ac945f1100995325

var cacheStack = require('cache-stack');

// fake a long operation that takes 1 second to the complete.
function longOp(onResult, stack) {
  setTimeout(function() {
    console.log('running longOp (should only be logged once)');
    onResult(null, 'ok', stack);
  }, 1000);
}

// bind our longOp and config to stacked
var stacked = cacheStack.bind(this, longOp, {
  expires: '+1 hour'
});

// Call stacked 3 times immediately. After 1 second (the 
// length of time our longOp takes to run), all 3 callbacks
// will be called.
stacked(callback);
stacked(callback);
stacked(callback);

// When we do another call to stacked, it will be returned the 
// cached version immediately.
setTimeout(function() {
  stacked(callback);
}, 2000);


var i = 0;
function callback(err, res) {
  console.log(res + ':' + i);
  i++;    
};