* @param {Boolean} [ensure=false] If true, intermediate keys that are `null` or
* `undefined` will be filled in with a new empty object `{}`, ensuring the get will
* return valid metadata.
- * @retruns {null|Object} If found, the object is of the form `{ key: Qualified key name, obj: Parent object of key, val: Value at obj[key] }`. Otherwise `null`.
+ * @retruns {undefined|Object} If found, the object is of the form
+ * `{ key: Qualified key name, obj: Parent object of key, val: Value at obj[key] }`.
+ * Otherwise `undefined`.
*/
getNestedMeta : (obj, chain, ensure=false) ->
chain = chain.split('.') if typeof chain is 'string'
_.reduce do
chain
(current, key, idx, chain) ->
- return null unless current?
+ return undefined unless current?
if idx is chain.length-1
return
else if ensure
current[key] = {}
else
- null
+ undefined
obj
/**
* @param {Boolean} [ensure=false] If true, intermediate keys that are `null` or
* `undefined` will be filled in with a new empty object `{}`, ensuring the set
* will succeed.
- * @retruns {null|Any} If found, returns the old value, and otherwise `null`.
+ * @retruns {undefined|Any} If found, returns the old value, and otherwise `undefined`.
*/
setNested : (obj, chain, value, ensure=false) ->
meta = _obj.getNestedMeta obj, chain, ensure
meta.obj[meta.key] = value
meta.val
else
- null
+ undefined
+
+ /**
+ * Searches a heirarchical object for a given subkey specified in
+ * dotted-property syntax, removing it if found.
+ * @param {Object} obj The object to serve as the root of the property-chain.
+ * @param {Array|String} chain The property-chain to lookup.
+ * @param {Boolean} [ensure=false] If true, intermediate keys that are `null` or
+ * `undefined` will be filled in with a new empty object `{}`, ensuring the set
+ * will succeed.
+ * @retruns {undefined|Any} If found, returns the old value, and otherwise `undefined`.
+ */
+ unsetNested : (obj, chain, ensure=false) ->
+ meta = _obj.getNestedMeta obj, chain, ensure
+ if meta
+ delete meta.obj[meta.key]
+ meta.val
+ else
+ undefined
exports import _obj
_ = require 'kraken/underscore'
+
/**
* @class A mapping of key-value pairs supporting lookup fallback across multiple objects.
*/
class Cascade
/**
+ * Map holding the object's KV-pairs. It is also the first element of the
+ * cascade lookup.
+ * @type Object
+ * @private
+ */
+ _data : null
+
+ /**
* List of objects for lookups.
* @type Array
* @private
*/
- _dicts : null
+ _lookups : null
+
/**
* @constructor
*/
- ->
- @_dicts = []
- @extend ...
+ (data={}, lookups=[]) ->
+ @_data = {} import data
+ @_lookups = [@_data].concat lookups.slice()
/**
- * @returns {Number} Number of real keys in the Dict.
+ * @returns {Cascade} A copy of the lookup chain.
*/
- size : ->
- _.keys @_dicts .length
+ clone: ->
+ new Cascade @_data, @_lookups
+
+
+
+ ### Lookups ###
/**
- * @returns {Cascade} A copy of the dict, including fallbacks as well as data.
+ * Adds a new lookup dictionary to the chain.
+ * @returns {this}
*/
- clone: ->
- d = new Cascade
- _.each @_dicts, (v, k) ->
- d.setAlias k, v.slice()
- d
+ addLookup: (dict) ->
+ @_lookups.push dict
+ this
+
+ /**
+ * Removes a lookup dictionary from the chain.
+ * @returns {this}
+ */
+ removeLookup: (dict) ->
+ _.remove @_lookups, dict
+ this
+
* @returns {Boolean} Whether there is a value at the given key.
*/
has : (key) ->
- (@get key, null)?
+ (@get key, undefined) is not undefined
+
/**
- * @returns {*} Ignores aliases, returning the value at key or `undefined`.
+ * @returns {*} First value for the given key found in the lookup chain,
+ * and the default otherwise.
*/
- getValue : (key) ->
- prop = _.getNested @_dicts, key
- prop.value if prop?
-
get : (key, def) ->
- aliases = @_aliases[key] or [key]
- val = aliases.reduce do
- (val, alias) ->
- return val if val? is not undefined
- prop = _.getNested @_dicts, alias
- prop.value if prop?
- undefined
-
- if val is not undefined
- val
- else
- def
+ for data of @_lookups
+ val = _.getNested data, key, undefined
+ return val if val is not undefined
+ def
+ /**
+ * @param {String} key Key to set.
+ * @param {*} val Non-`undefined` value to set.
+ * @returns {this}
+ */
set : (key, val) ->
- _.setNested @_dicts, key, val, true
- val
+ throw new Error("Value and key cannot be undefined!") unless key and val is not undefined
+ _.setNested @_data, key, val
+ this
- del : (key) ->
- prop = _.getNestedMeta key
- if prop
- delete prop.obj[prop.key]
- prop.value
+ /**
+ * Delete the given key from this object's concrete data. If missing,
+ * does not cascade.
+ * @returns {undefined|*} If found, returns the old value, and otherwise `undefined`.
+ */
+ del: (key) ->
+ _.unsetNested @_data, key, false
### Collection Methods ###
+ extend : (...args) ->
+ for o of args
+ for k,v in o then @set k, v
+ this
+
toObject: ->
- _.extend {}, ...@_dicts
+ _.extend {}, ...@_lookups
- # XXX: Merge keys from all objects?
keys: ->
- _.keys @_data
+ _.flatten _.map @_lookups, -> _.keys it
values: ->
- _.values @_data
-
- extend : (...args) ->
- for o of args
- for k,v in o then @set k, v
- this
+ _.flatten _.map @_lookups, -> _.values it
reduce : (fn, acc, context=this) ->
- _.reduce @_data, fn, acc, context
+ _.reduce @_lookups, fn, acc, context
map : (fn, context=this) ->
- _.map @_data, fn, context
+ _.map @_lookups, fn, context
filter: (fn, context=this) ->
- _.filter @_data, fn, context
+ _.filter @_lookups, fn, context
each : (fn, context=this) ->
- _.each @_data, fn, context
+ _.each @_lookups, fn, context
this
invoke : (name, ...args) ->
- _.invoke @_data, name, ...args
+ _.invoke @_lookups, name, ...args
pluck : (attr) ->
- _.pluck @_data, attr
+ _.pluck @_lookups, attr
find: (fn, context=this) ->
- _.find @_data, fn, context
+ _.find @_lookups, fn, context
toString: ->
- Cls = @.constructor
+ Cls = this.constructor
"#{Cls.displayName or Cls.name}()"
projects / limn-bak.git / commitdiff