Melt.js

Javascript library inspired by the R reshape package by Hadley Wickham.

Melt provides two functions melt and cast. How do they work?

First, they presume you have your data in the form of a list of objects. That looks like this:

var data = [
  {key1: 1, key2: 2},
  {key1: 2, key2: 3},
  {key1: 3, key2: 5},
];

But if you need the keys to be represented as a value, then melt can come to the rescue. Let's take a look at some examples:

Examples

Melt: jsfiddle

Cast: jsfiddle

API

melt(data, keep, varName, valName, noAddId)

• data list of objects - data to melt
• keep array of strings - names of object keys to keep
• varName string - name of the key to use in the molten objects for the former keys (those not in keep)
• valName string - name of the key to use in the molten objects for the former values
• noAddId bool - if truthy, don't add the _id value to the resulting object

cast(data, keep, fun, funArgs ...)

• data list of objects - data to cast
• keep array of strings - names of object keys to keep (the "GROUP BY" keys)
• fun function - a function used to aggregate values accross grouped objects
• funArgs mixed - arguments to passed to fun

cast.sum(name, cols) - convience function to summarize data with cast

• name string name of resulting object key with sum results
• cols string or array - names of keys to totaled in the sum. Key values should respond to +.

cast.sum(name) - convience function to sum data with cast

• name string - special case of cast.sum(name, cols) name is treated as both name and cols.

cast.count(name) - convience function to count data with cast

• name string - name of resulting object key with which to count objects with common keep values

License

Apache 2