remodeler

node.js module to transform objects into new objects, by copying or renaming properties, but also allowing for functional transformations. These are provided via key / transformation pairs.

For example, if an outside module is using Coding by Convention, but you just aren't, or can't, use their convention, this module could be useful in creating a new object meeting that convention. For more background see my blog post.

This can also be thought of as a quick and dirty Adapter pattern.

As for the key / transformation paris, the key will be the new key in the new object.

The transformation may be one of the following:

• null: first, check this.defaultTransformation. If that is null, do nothing (ignore this field)
• string: newObject[key] = oldObject[string] copy from old object, string = oldKey
• function: newObject[key] = function(oldObject, key)

usage

In this example we are converting an object to a more iCal / iCalendar / .ics friendly format. (Warning: example is incomplete and DTSTART tag is incorrect)

    var Remodeler = require('remodeler');
    var input = { 
      UID: '[email protected]',
      name: 'Supercool Meetup',
      location: 'Palo Alto CA',
      when: new Date()
    };
   
    var myRemodeler = new Remodeler();
    myRemodeler.copyKeys(Object.keys(input)).excludeKeys('when');
   
    myRemodeler.addKeyXformPairs(
      'DTSTART', function(o) {
         return 'DTSTART;VALUE=DATE_TIME:' + o.when.toISOString();
      },
      'DESCRIPTION', function(o) {
         return o.name + '@' + o.location;
      });
      
    var out = myRemodeler.remodel(input);
   
    out will be an object:
    {
     "UID":"[email protected]",
     "name":"Supercool Meetup",
     "location":"Palo Alto CA",
     "DTSTART":"DTSTART;VALUE=DATE_TIME:2014-06-11T23:40:59.538Z",
     "DESCRIPTION":"Supercool Meetup@Palo Alto CA"
    }

API

Remodeler(options, initMap)

Constructor. Usually, options and initMap can be left or or set to null. Current options are:

• isPassThrough if true, remodel() (see below) will simply return src.
• defaultTransformation Will be used if a specific key Transformation is null. If initMap is present, addKeyXformMap(initMap) is called.

copyKeys(keys)

the keys (a single String or an array of Strings) will be copied as is. For example, to copy everything: copyKeys(Object.keys(srcObject))

excludeKeys(keys)

the keys (a single String or an array of Strings) will be excluded

addKeyXformArray(array)

array[0,2,4...] = keys, array[1,3,5...] = corresponding transformation

addKeyXformMap(map)

map consists of key/value pairs, key = key, value = transformation

addKeyXformPairs(k1,t1,k2,t2...)

similar to addKeyXformArray, except arguments[0,2,4...] = keys, arguments[1,3,5...] = transformations

remodel(src, dst)

Transforms src into dst based upon current configuration and values. If dst is null (typical) a new {} will be created, added to, and returned.