Data Pivot (pivot.js)

Status: early version!

pivot makes it easy to rearrange JSON objects (or other objects). It takes 3 arguments, then you call run():

pivot(data, inputSchema, outputSchema).run()

The schemas use a simple string format like this: "top-key -> middle-key -> value". You can call the keys anything you like - they get matched between inputSchema and outputSchema.

pivot can sum numbers and collect multiple values into arrays (this and other settings can be configured).

Let's see a few examples:

Installation: No dependencies, just one small file

In html? Download pivot.js, then use: <script src='pivot.js'></script>

In node? npm install data-pivot

Javascript (pivot.js)

var mydata = {
  monday: {apples:1},
  tuesday: {apples:2, pears:1}
}

// Reverse the map: What day did I buy pears?  
var daysByFruit = pivot(mydata,'day -> fruit -> n', 'fruit -> day').run();  
// Multiple values become an array, single values are left as-is.
// So the output is {apples:['monday','tuesday'], pears:'tuesday'}

// Suppose we always want arrays, even if there's only one value.
// Use mode('array') like this:
var daysByFruit = pivot(mydata,'day -> fruit -> n', 'fruit -> day').mode('array').run();  
// output is {apples:['monday','tuesday'], pears:['tuesday']}

// Forget the day (this will sum over the days)
var totalPerFruit = pivot(mydata,'day -> fruit -> n', 'fruit -> n').run();  
// output is {apples:3, pears:1}

Python (pivot.py)

Also available in Python! The Python version is included here -- see pivot.py