treeize

treeize

Converts row data (in JSON/associative array format) to object/tree structure based on column naming conventions.

##Why?

Most of us still have our hands in traditional relational databases (e.g. MySQL). While the normalized tables do a fine job of representing the parent/child relationships, the joined SQL results do not. In fact, they look more like an Excel spreadsheet than anything. This presents us with a problem when trying to supply a nice deep object graph for applications.

Using a traditional ORM is slow (either many fragmented SQL calls, slow object hydration of models, or both). Beyond that, for a lightweight API, you don't want to have to first pick an ORM and then model out all your relationships. For complex queries, especially where results are filtered by multiple columns across multiple tables, it becomes even more troublesome, or borderline impossible to use these model helpers.

The problem is, you can write the complex deeply joined SQL call that has all the results you wanted - but you can't get it back into an object graph so it looks/behaves like something other than data vomit.

Now you can.

Installation

npm install treeize

API

• treeize.grow(flatData, [options]) - takes your results/rows of flat associative data and returns a full object graph.

Configuration (first value is default)

treeize.options([options]); // universal getter/setter for options.  Returns self.

// default options are as follows:

{
  delimiter:        ':',          // Path delimiter, as in "foo:bar:baz"
  collections: {
    auto:           true          // Defaults to pluralized detection for collections.
                                  // Setting to false requires + operators for
                                  // every collection.
  }
}

Usage

To use treeize, simply pass flat "row data" into treeize.grow(). Each column/attribute of each row will dictate its own destination path using the following format:

{
  "[path1]:[path2]:[pathX]:[attributeName]": [value]
}

Each "path" (up to n-levels deep) is optional and represents a single object node if the word is singular, or a collection if the word is plural. For example, a "favoriteMovie:name" path will add a "favoriteMovie" object to its path - where "favoriteMovies:name" would add a collection of movies (complete with a first entry) instead. For root nodes, include only the attribute name without any preceding paths. If you were creating a final output of a book collection for instance, the title of the book would likely be pathless as you would want the value on the high-level collection book object.

It's important to note that each row will create or find its path within the newly transformed output being created. Your flat feed will have mass-duplication, the results will not.

How to manually override the default pluralization scheme for collection-detection

In the rare (but possible) case that plural/singular node names are not enough to properly detect collections, you may add specific overrides to the node name, using the + and - indicators.

{
  "name":                 "Bird",
  "attributes:legs":      2,
  "attributes:hasWings":  true
}

// would naturally return

[
  {
    name: "Bird",
    attributes: [
      {
        legs: 2,
        hasWings: true
      }
    ]
  }
]

// to tell treeize that the node (detected as a plural collection)
// is NOT a collection, add a - to the path

{
  "name":                 "Bird",
  "attributes-:legs":      2,
  "attributes-:hasWings":  true
}

// results in

[
  {
    name: "Bird",
    attributes: {
      legs: 2,
      hasWings: true
    }
  }
]

// conversely, add a + to a path to force it into a collection

Pathing example

{
  "title": "Ender's Game",                      // creates the first object with a title attribute of "Ender's Game"
  "author:name": "Orson Scott Card",            // adds an author object (with name) to the book "Ender's Game" (created above)
  "author:age":  21,                            // gives the author object an age attribute
  "author:otherBooks:title": "Ender's Shadow",  // adds a collection named "otherBooks" to the author, with a first object of "title": "Ender's Shadow"
}

// creates the following...

[
  {
    title: "Ender's Game",
    author: {
      name: "Orson Scott Card",
      age: 21,
      otherBooks: [
        { title: "Ender's Shadow" }
      ]
    }
  }
]

Notes

• The column/attribute order is not important. All attributes are sorted by depth before mapping. This ensures parent nodes exist before children nodes are created within.
• Each attribute name of the flat data must consist of the full path to its node & attribute, seperated by the delimiter. id suggests an id attribute on a root element, whereas name:first implies a first attribute on a name object within a root element.
• To imply a collection in the path/attribute-name, use a plural name (e.g. "subjects" instead of "subject"). Otherwise, use a singular name for a singular object.
• Use a : delimiter (default) to seperate path nodes. To change this, use the treeize.set([options]) function.

Assumptions

This library has several assumptions that make it possible.

1. That each row represents a singular child item, that may contain many repeated ancestor columns.
2. That each element in a collection node (including the root) will have a unique identifying signature (necessary to prevent duplication). This can be any one attribute, or the combination of any/all attributes.

Examples

In this short series of examples, we'll take a standard "join dump", originally keyed (via attribute names) to organize by movie - and demonstrate how other organizations can be easily derived from the same original feed... by simply modifying the column/attribute names in the output.

Example 1

In this example, we'll take our dump (as if from a CSV or SQL result) - and name the keys to group by movies (as if for an /api/movies).

var treeize = require('treeize');

var movieDump = [
  {
    "title":             "The Prestige",
    "director":          "Christopher Nolan",
    "actors:name":       "Christian Bale",
    "actors:as":         "Alfred Borden"
  },
  {
    "title":             "The Prestige",
    "director":          "Christopher Nolan",
    "actors:name":       "Hugh Jackman",
    "actors:as":         "Robert Angier"
  },
  {
    "title":             "The Dark Knight Rises",
    "director":          "Christopher Nolan",
    "actors:name":       "Christian Bale",
    "actors:as":         "Bruce Wayne"
  },
  {
    "title":             "The Departed",
    "director":          "Martin Scorsese",
    "actors:name":       "Leonardo DiCaprio",
    "actors:as":         "Billy"
  },
  {
    "title":             "The Departed",
    "director":          "Martin Scorsese",
    "actors:name":       "Matt Damon",
    "actors:as":         "Colin Sullivan"
  }
];

var movies = treeize.grow(movieDump);

/*

  'movies' now contains the following:

  [
    {
      "director": "Christopher Nolan",
      "title": "The Prestige",
      "actors": [
        {
          "as": "Alfred Borden",
          "name": "Christian Bale"
        },
        {
          "as": "Robert Angier",
          "name": "Hugh Jackman"
        }
      ]
    },
    {
      "director": "Christopher Nolan",
      "title": "The Dark Knight Rises",
      "actors": [
        {
          "as": "Bruce Wayne",
          "name": "Christian Bale"
        }
      ]
    },
    {
      "director": "Martin Scorsese",
      "title": "The Departed",
      "actors": [
        {
          "as": "Billy",
          "name": "Leonardo DiCaprio"
        },
        {
          "as": "Colin Sullivan",
          "name": "Matt Damon"
        }
      ]
    }
  ]

*/

Example 2

Taking the same feed, but modifying the target paths through the attribute/column names we can completely transform the data (as you would for another API endpoint, for example). This time we'll organize the data by actors, as you would for and endpoint like /api/actors.

Notice the feed is left unchanged - only the attribute names have been modified to define their new target path. In this case, by changing the base node to the actor name (instead of the movie name), we group everything by actor at a high level.

var treeize = require('treeize');

var moviesDump = [
  {
    "movies:title":     "The Prestige",
    "movies:director":  "Christopher Nolan",
    "name":             "Christian Bale",
    "movies:as":        "Alfred Borden"
  },
  {
    "movies:title":     "The Prestige",
    "movies:director":  "Christopher Nolan",
    "name":             "Hugh Jackman",
    "movies:as":        "Robert Angier"
  },
  {
    "movies:title":     "The Dark Knight Rises",
    "movies:director":  "Christopher Nolan",
    "name":             "Christian Bale",
    "movies:as":        "Bruce Wayne"
  },
  {
    "movies:title":     "The Departed",
    "movies:director":  "Martin Scorsese",
    "name":             "Leonardo DiCaprio",
    "movies:as":        "Billy"
  },
  {
    "movies:title":     "The Departed",
    "movies:director":  "Martin Scorsese",
    "name":             "Matt Damon",
    "movies:as":        "Colin Sullivan"
  }
];

var actors = treeize.grow(movieDump);

/*

  'actors' now contains the following:

  [
    {
      "name": "Christian Bale",
      "movies": [
        {
          "as": "Alfred Borden",
          "director": "Christopher Nolan",
          "title": "The Prestige"
        },
        {
          "as": "Bruce Wayne",
          "director": "Christopher Nolan",
          "title": "The Dark Knight Rises"
        }
      ]
    },
    {
      "name": "Hugh Jackman",
      "movies": [
        {
          "as": "Robert Angier",
          "director": "Christopher Nolan",
          "title": "The Prestige"
        }
      ]
    },
    {
      "name": "Leonardo DiCaprio",
      "movies": [
        {
          "as": "Billy",
          "director": "Martin Scorsese",
          "title": "The Departed"
        }
      ]
    },
    {
      "name": "Matt Damon",
      "movies": [
        {
          "as": "Colin Sullivan",
          "director": "Martin Scorsese",
          "title": "The Departed"
        }
      ]
    }
  ]

*/