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@dtipson
Created April 24, 2017 20:58
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Experimenting with a type that contains objects that are listed in insertion order but are also unique by a single chosen prop
const getProp = prop => object => object[prop]
function KeyedCollection (Iterable, prop){
if (!(this instanceof KeyedCollection)) {
return new KeyedCollection(Iterable, prop);
}
if(!prop){
throw new Error('must supply a prop')
}
const it_target = []
const selectPropFrom = getProp(prop)
//Functor.map(obj=>[getProp(prop)(obj),obj])
for (item of Iterable){
it_target.push([String(selectPropFrom(item)),item])
}
this.selectPropFrom = selectPropFrom
this.prop = prop;
this.map = new Map(
it_target
)
}
KeyedCollection.prototype.get = function(key){
return this.map.get(String(key))//mutates!
}
KeyedCollection.prototype.has = function(key){
return this.map.has(String(key))
}
KeyedCollection.prototype.size = function(){
return this.map.size()
}
KeyedCollection.prototype.clear = function(){
return this.map.clear()
}
KeyedCollection.prototype.delete = function(key){
return this.map.delete(key)//mutates!
}
KeyedCollection.prototype[Symbol.iterator] = function* (){
for (let [k,v] of this.map){
yield v
}
}
KeyedCollection.prototype.addFromArray = function(ArrayOfObjects){
for (obj of ArrayOfObjects){
this.map.set(this.selectPropFrom(obj),obj)
}
return this;
}
//another attempt to save an iteration.... [...KeyedCollection.toReact(Component)]
KeyedCollection.prototype.toReact = function *(Component){
for (let [key,v] of this.map){
yield Component(Object.assign(v,{key}))//is key getting assigned in the React way here?
//have to actually try this out...
}
}
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