From 41d4de590e6c2a428aa58dbaa459db7ac9710bec Mon Sep 17 00:00:00 2001
From: Kir_Antipov <kp.antipov@gmail.com>
Date: Wed, 18 Jan 2023 12:28:01 +0000
Subject: [PATCH] Implemented enum descriptor for string enums

---
 .../enum/descriptors/string-descriptor.ts     | 68 +++++++++++++++++++
 .../descriptors/string-descriptor.spec.ts     | 47 +++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 src/utils/enum/descriptors/string-descriptor.ts
 create mode 100644 tests/unit/utils/enum/descriptors/string-descriptor.spec.ts

diff --git a/src/utils/enum/descriptors/string-descriptor.ts b/src/utils/enum/descriptors/string-descriptor.ts
new file mode 100644
index 0000000..ab27084
--- /dev/null
+++ b/src/utils/enum/descriptors/string-descriptor.ts
@@ -0,0 +1,68 @@
+import { split } from "@/utils/string-utils";
+import { ENUM_SEPARATORS, DEFAULT_ENUM_SEPARATOR } from "../enum-separators";
+import { EnumDescriptor } from "./enum-descriptor";
+
+/**
+ * This descriptor is used to describe a set of flags stored as a `string` value.
+ *
+ * @remarks
+ *
+ * It's super inefficient, when it comes to flags, because the whole concept
+ * of string flags just seems too shady to me to optimize for these scenarios.
+ * So, string enums are ok, but string enums with flags are not recommended.
+ */
+export class StringDescriptor implements EnumDescriptor<string> {
+    /**
+     * @inheritdoc
+     */
+    get name(): "string" {
+        return "string";
+    }
+
+    /**
+     * @inheritdoc
+     */
+    get defaultValue(): string {
+        return "";
+    }
+
+    /**
+     * @inheritdoc
+     */
+    hasFlag(value: string, flag: string): boolean {
+        if (flag === this.defaultValue || flag === value) {
+            return true;
+        }
+
+        if (!value) {
+            return false;
+        }
+
+        const flags = split(value, ENUM_SEPARATORS, { trimEntries: true, removeEmptyEntries: true });
+        return flags.includes(flag);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    addFlag(value: string, flag: string): string {
+        value = this.removeFlag(value, flag);
+        return value ? `${value}${DEFAULT_ENUM_SEPARATOR} ${flag}` : value;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    removeFlag(value: string, flag: string): string {
+        if (value === this.defaultValue || flag === this.defaultValue) {
+            return value;
+        }
+
+        if (value === flag) {
+            return this.defaultValue;
+        }
+
+        const flags = split(value, ENUM_SEPARATORS, { trimEntries: true, removeEmptyEntries: true });
+        return flags.filter(x => x !== flag).join(DEFAULT_ENUM_SEPARATOR + " ");
+    }
+}
diff --git a/tests/unit/utils/enum/descriptors/string-descriptor.spec.ts b/tests/unit/utils/enum/descriptors/string-descriptor.spec.ts
new file mode 100644
index 0000000..12e5cf3
--- /dev/null
+++ b/tests/unit/utils/enum/descriptors/string-descriptor.spec.ts
@@ -0,0 +1,47 @@
+import { StringDescriptor } from "@/utils/enum/descriptors/string-descriptor";
+
+describe("StringDescriptor", () => {
+    const descriptor = new StringDescriptor();
+
+    describe("name", () => {
+        test("returns 'string' as name", () => {
+            expect(descriptor.name).toBe("string");
+        });
+    });
+
+    describe("defaultValue", () => {
+        test("returns '' as default value", () => {
+            expect(descriptor.defaultValue).toBe("");
+        });
+    });
+
+    describe("hasFlag", () => {
+        test("returns true if flag is set", () => {
+            expect(descriptor.hasFlag("value1, value2, value3", "value2")).toBe(true);
+        });
+
+        test("returns false if flag is not set", () => {
+            expect(descriptor.hasFlag("value1, value2, value3", "value4")).toBe(false);
+        });
+    });
+
+    describe("addFlag", () => {
+        test("adds flag to value", () => {
+            expect(descriptor.addFlag("value1, value2", "value3")).toBe("value1, value2, value3");
+        });
+
+        test("does not add flag if it is already set", () => {
+            expect(descriptor.addFlag("value1, value2, value3", "value3")).toBe("value1, value2, value3");
+        });
+    });
+
+    describe("removeFlag", () => {
+        test("removes flag from value", () => {
+            expect(descriptor.removeFlag("value1, value2, value3", "value2")).toBe("value1, value3");
+        });
+
+        test("does not remove flag if it does not exist", () => {
+            expect(descriptor.removeFlag("value1, value2", "value3")).toBe("value1, value2");
+        });
+    });
+});