area51/test/es6/symbol-tests.js

Experimental prototypes of alien things built in JavaScript. The bits may end up living in a different package.

var assert = require("assert");
var Symbol = require("../../lib/es6/symbol");

module.exports = {
	"Symbol": {
		"create symbol": function(){ 
			var local = Symbol();
			assert.ok(local != null, "symbol must not be null");
			assert.ok(local instanceof Symbol, "symbol must be type Symbol");
		},
		"Symbol.for - returns global symbol": function() {
			var global = Symbol.for("desc");
			var g2 = Symbol.for("desc");
			
			assert.ok(global !== null, "global is not null");
			assert.equal(global, g2);
		},
		"Symbol.forKey - returns description": function() {
			var global = Symbol.for("desc");
			var key = Symbol.keyFor(global);
			
			assert.equal("desc", key);	
			
			var local = Symbol();
			key = Symbol.keyFor(local);
			assert.equal(undefined, key);
		},
		"local symbols create new symbol": function() {
			var l1 = Symbol();
			var l2 = Symbol();
			
			assert.notEqual(l1, l2);
		},
		"local symbols are not global": function() {
			var l1 = Symbol("desc");
			var g1 = Symbol.for("desc");
			
			assert.notEqual(l1, g1, "l1 is not equal to g1");
		},
		"object property use case": function() {
			var g1 = Symbol.for("desc");
			
			var obj = {};
			obj[g1] = "value";
			
			assert.equal("value", obj[g1]);
			assert.equal(undefined, obj["g1"]);
			assert.equal(undefined, obj["desc"]);
			
			var results = Object.getOwnPropertySymbols(obj);
			assert.ok(Array.isArray(results));
			assert.equal(g1, results[0]);
			
			// verify symbol properties are not enumerable.
			var failures = [];
			for(var prop in obj) {
				failures.push(prop);
			}
			assert.equal(0, failures.length, "symbol properties are not enumerable");
		}
	}
};