copied set implementations from MultiFlag JS

node/tests/_archive/flagset.test.ts

@@ -0,0 +1,25 @@
+import { NumberBitflagSet, ReusedFlagValueError } from '@module'
+
+test('cannot create an abstract flag with less than two parents', () => {
+    const flags = new NumberBitflagSet()
+    const flag1 = flags.flag(1)
+
+    expect(() => flags.flag()).toThrow(TypeError)
+    expect(() => flags.flag(flag1)).toThrow(TypeError)
+    expect(() => flags.flag(flag1, flag1)).toThrow(TypeError)
+})
+
+test('calls to flag() with arguments in the wrong order throw a TypeError', () => {
+    const flags = new NumberBitflagSet()
+    const flag1 = flags.flag(1)
+    const flag2 = flags.flag(2)
+
+    // @ts-ignore
+    expect(() => flags.flag(flag1, 2, flag2)).toThrow(TypeError)
+})
+
+test('Use same value twice', () => {
+    const flags = new NumberBitflagSet()
+    const flag = flags.flag(1)
+    expect(() => flags.flag(1)).toThrow(ReusedFlagValueError)
+})