I have a problem where I'm generating many values and need to make sure I only work with unique ones. Since I'm using node js, with the --harmony flag, and have access to harmony collections, I decided that a Set may be an option.
What I'm looking for is something similar to the following example:
'use strict';
function Piece(x,y){
this.x = x
this.y = y
}
function Board(width,height,pieces){
this.width = width
this.height = height
this.pieces = pieces
}
function generatePieces(){
return [
new Piece(0,0),
new Piece(1,1)
]
}
//boardA and boardB are two different but equivalent boards
var boardA = new Board(10,10,generatePieces())
var boardB = new Board(10,10,generatePieces())
var boards = new Set()
boards.add(boardA)
boards.has(boardB) //return true
Now normally to achieve this in another language, say c#, I would expect to have to implement an equals function, as well as a hash code generating function for both Board and Piece. Since I'd expect the default object equality to be based on references. Or perhaps use a special immutable value type (say, a case class in scala)
Is there a means to define equality for my objects to solve my problem?
No not really. There has been some discussion about this on the mailing list. The result is: