Add in-place set functions

Yomguithereal · Apr 13, 2017 · d3e6122 · d3e6122
1 parent 94c1194
commit d3e6122
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diff --git a/set.js b/set.js
@@ -138,4 +138,112 @@ exports.symmetricDifference = function(A, B) {
   return S;
 };
 
-// TODO: subset, superset, in-place
+/**
+ * Function returning whether A is a subset of B.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ * @return {boolean}
+ */
+exports.isSubset = function(A, B) {
+  var iterator = A.values(),
+      step;
+
+  while ((step = iterator.next(), !step.done)) {
+    if (!B.has(step.value))
+      return false;
+  }
+
+  return true;
+};
+
+/**
+ * Function returning whether A is a superset of B.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ * @return {boolean}
+ */
+exports.isSuperset = function(A, B) {
+  return exports.isSubset(B, A);
+};
+
+/**
+ * Function adding the items of set B to the set A.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ */
+exports.add = function(A, B) {
+  var iterator = B.values(),
+      step;
+
+  while ((step = iterator.next(), !step.done))
+    A.add(step.value);
+
+  return;
+};
+
+/**
+ * Function subtracting the items of set B from the set A.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ */
+exports.subtract = function(A, B) {
+  var iterator = B.values(),
+      step;
+
+  while ((step = iterator.next(), !step.done))
+    A.delete(step.value);
+
+  return;
+};
+
+/**
+ * Function intersecting the items of A & B.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ */
+exports.intersect = function(A, B) {
+  var iterator = A.values(),
+      step;
+
+  while ((step = iterator.next(), !step.done)) {
+    if (!B.has(step.value))
+      A.delete(step.value);
+  }
+
+  return;
+};
+
+/**
+ * Function disjuncting the items of A & B.
+ *
+ * @param  {Set} A - First set.
+ * @param  {Set} B - Second set.
+ */
+exports.disjunct = function(A, B) {
+  var iterator = A.values(),
+      step;
+
+  var toRemove = [];
+
+  while ((step = iterator.next(), !step.done)) {
+    if (B.has(step.value))
+      toRemove.push(step.value);
+  }
+
+  iterator = B.values();
+
+  while ((step = iterator.next(), !step.done)) {
+    if (!A.has(step.value))
+      A.add(step.value);
+  }
+
+  for (var i = 0, l = toRemove.length; i < l; i++)
+    A.delete(toRemove[i]);
+
+  return;
+};
diff --git a/test/set.js b/test/set.js
@@ -77,4 +77,66 @@ describe('Set functions', function() {
       assert.deepEqual(Array.from(S), [1, 2, 4, 5]);
     });
   });
+
+  describe('#.isSubset', function() {
+    it('should properly return if the first set is a subset of the second.', function() {
+      var A = new Set([1, 2]),
+          B = new Set([1, 2, 3]),
+          C = new Set([2, 4]);
+
+      assert.strictEqual(functions.isSubset(A, B), true);
+      assert.strictEqual(functions.isSubset(C, B), false);
+    });
+  });
+
+  describe('#.isSuperset', function() {
+    it('should properly return if the first set is a subset of the second.', function() {
+      var A = new Set([1, 2]),
+          B = new Set([1, 2, 3]),
+          C = new Set([2, 4]);
+
+      assert.strictEqual(functions.isSuperset(B, A), true);
+      assert.strictEqual(functions.isSuperset(B, C), false);
+    });
+  });
+
+  describe('#.add', function() {
+    it('should properly add the second set to the first.', function() {
+      var A = new Set([1, 2]);
+
+      functions.add(A, new Set([2, 3]));
+
+      assert.deepEqual(Array.from(A), [1, 2, 3]);
+    });
+  });
+
+  describe('#.subtract', function() {
+    it('should properly subtract the second set to the first.', function() {
+      var A = new Set([1, 2]);
+
+      functions.subtract(A, new Set([2, 3]));
+
+      assert.deepEqual(Array.from(A), [1]);
+    });
+  });
+
+  describe('#.intersect', function() {
+    it('should properly intersect the second set to the first.', function() {
+      var A = new Set([1, 2]);
+
+      functions.intersect(A, new Set([2, 3]));
+
+      assert.deepEqual(Array.from(A), [2]);
+    });
+  });
+
+  describe('#.disjunct', function() {
+    it('should properly disjunct the second set to the first.', function() {
+      var A = new Set([1, 2]);
+
+      functions.disjunct(A, new Set([2, 3]));
+
+      assert.deepEqual(Array.from(A), [1, 3]);
+    });
+  });
 });