add Union superset and subset methods

Author: victorpoughon

src/union.ts

@@ -30,6 +30,18 @@ export class Union {
         return this.intervals.some((i) => i.contains(value));
     }
 
+    public subset(other: Union): boolean {
+        return this.intervals.every((thisInterval) =>
+            other.intervals.some((otherInterval) => thisInterval.subset(otherInterval))
+        );
+    }
+
+    public superset(other: Union): boolean {
+        return other.intervals.every((otherInterval) =>
+            this.intervals.some((thisInterval) => thisInterval.superset(otherInterval))
+        );
+    }
+
     public hull(): Union {
         if (this.isEmpty()) return EMPTY;
         return single(this.lower(), this.upper());

tests/union.test.ts

@@ -23,4 +23,35 @@ describe("union", () => {
         assert.ok(ordered(nsf.union([nsf.interval(1, 2), nsf.interval(-10, -5)])));
         assert.ok(ordered(nsf.union([nsf.interval(1, 2), nsf.interval(-5, 5)])));
     });
+
+    it("union contains", () => {
+        const a = nsf.union([nsf.interval(0, 10), nsf.interval(50, 60)]);
+        assert.ok(!nsf.EMPTY.contains(0));
+        assert.ok(a.contains(0));
+        assert.ok(a.contains(1));
+        assert.ok(a.contains(50));
+        assert.ok(a.contains(55));
+        assert.ok(a.contains(60));
+        assert.ok(!a.contains(61));
+        assert.ok(!a.contains(49));
+        assert.ok(!a.contains(-1));
+        assert.ok(!a.contains(15));
+    });
+
+    it("union subset", () => {
+        const a = nsf.union([nsf.interval(0, 10), nsf.interval(50, 60)]);
+        assert.ok(a.subset(nsf.single(0, 100)));
+        assert.ok(a.subset(nsf.FULL));
+        assert.ok(a.subset(nsf.union([nsf.interval(-1, 11), nsf.interval(45, 65)])));
+
+        assert.ok(nsf.EMPTY.subset(nsf.FULL));
+    });
+
+    it("union superset", () => {
+        const a = nsf.union([nsf.interval(0, 10), nsf.interval(50, 60)]);
+        assert.ok(a.superset(nsf.single(0, 1)));
+        assert.ok(a.superset(nsf.EMPTY));
+        assert.ok(a.superset(nsf.union([nsf.interval(2, 3), nsf.interval(5, 6)])));
+        assert.ok(nsf.FULL.superset(nsf.EMPTY));
+    });
 });