A path based set where the most specific path wins.

Synopsis

var assert = require('assert')
var supersede = require('supersede')

// create a set
var set = new Supersede

// set a value keyed to a path of depth 2.
set.set('.hello.world'.split('.'), 'hello, world')

// get the value
assert.equal(set.get('.hello.world'), 'hello, world')

// get a non-existant value
assert.equal(set.get('.hello.earth'), null)

// set a value keyed to a path of depth 1.
assert.equal(set.get('.hello'), 'hello, you')

// parent value is used
assert.equal(set.get('.hello.earth'), 'hello, earth')

// the most specific path wins
assert.equal(set.get('.hello.world'), 'hello, world')

// gather along a path
assert.deepEqual(set.gather('.hello.world'), [ 'hello, earth', 'hello, world' ])

Usage

Keys are generated by calling split('.') on a path string that begins with a dot '.' where path steps are dot '.' delimited.

var assert = require('assert')

var rootPath = '.'.split('.')
var otherPath = '.hello.world'.split('.')

assert.deepEqual(rootPath, [ '', '' ])
assert.deepEqual(otherPath, [ '', 'hello', 'world' ])

Supersede does not perform this split itself because if you're really in a hurry you might want to save the generated arrays for later use, or type out the key as an array literal.

supersede = new Supersede

Create an empty set.

supersede.set(path, value)

Sets a key to the given value overriding any key.

supersede.gather(path, value)

Gathers the values along the given path into an array. If there are no values along the path an empty array is returned.

supersede.remove(path)

Removes the value of the node specified by the given path.

Diary

The star '*' here is special and needs to be used carefully. Using it to remove all might not be the best.

What if we want to register a listener, so we place a '*' in the tree itself? Then we can search a path where we look for everything that is the given step or a star, but now we are getting into some recursive pattern matching. Do we really want to match '*' star?

signal.on('system.web.rost', handler1)
signal.on('system.*.error', handler2)

signal.on('system.web.logger.info', logger.info)

What is going to be useful? So much thought to put into late binding.

The only place that is useful is in gather, so I can make a new function that respsects that, but it would be slightly more expensive than gather, but only slightly more. It will not be universal. It can only be for '*'.