From 44096a7e69567565ec1856ced1b20b9e64115262 Mon Sep 17 00:00:00 2001
From: Pavel Bocharov <pv-bocharov@yandex-team.ru>
Date: Fri, 22 Oct 2021 11:56:39 +0300
Subject: [PATCH] Skip private members with decorators

---
 README.md                                     |  1 +
 src/properties-minifier.ts                    |  7 ++++-
 tests/functional-test-cases.ts                |  1 +
 .../private-with-decorators/input.ts          | 17 +++++++++++
 .../private-with-decorators/output.js         | 29 +++++++++++++++++++
 5 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 tests/test-cases/private-with-decorators/input.ts
 create mode 100644 tests/test-cases/private-with-decorators/output.js

diff --git a/README.md b/README.md
index a189a4c..c3b309f 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@ A TypeScript custom transformer which minify names of private class members.
 For now it just renames private members with prepending some prefix to name.
 For example, if you have `privateMember`, then after transformation the name will be `_private_privateMember`.
 After that you can use terser/uglify with mangle options to minify that members.
+Note, that private class members with decorators won't be prefixed and further minified.
 
 ## Caution!!!
 
diff --git a/src/properties-minifier.ts b/src/properties-minifier.ts
index bb1bd7c..34cccb1 100644
--- a/src/properties-minifier.ts
+++ b/src/properties-minifier.ts
@@ -190,6 +190,11 @@ function isPrivateNonStaticClassMember(symbol: ts.Symbol | undefined): boolean {
 	}
 
 	return symbol.declarations.some((x: ts.Declaration) => {
-		return (isClassMember(x) || isConstructorParameter(x)) && isPrivateNonStatic(x);
+		// terser / uglify property minifiers aren't able to handle decorators
+		return (isClassMember(x) && !hasDecorators(x) || isConstructorParameter(x)) && isPrivateNonStatic(x);
 	});
 }
+
+function hasDecorators(node: ts.Node): boolean {
+	return !!node.decorators;
+}
diff --git a/tests/functional-test-cases.ts b/tests/functional-test-cases.ts
index c48aa01..ed7ebd9 100644
--- a/tests/functional-test-cases.ts
+++ b/tests/functional-test-cases.ts
@@ -75,6 +75,7 @@ describe('Functional tests', () => {
 				rootNames: [testCase.inputFileName],
 				options: {
 					target: ts.ScriptTarget.ES5,
+					experimentalDecorators: true,
 				},
 			});
 
diff --git a/tests/test-cases/private-with-decorators/input.ts b/tests/test-cases/private-with-decorators/input.ts
new file mode 100644
index 0000000..35b5189
--- /dev/null
+++ b/tests/test-cases/private-with-decorators/input.ts
@@ -0,0 +1,17 @@
+export class Class {
+	public publicField: number = 123;
+	//@ts-ignore
+	@decorator private privateField: string = 'string-value';
+
+	public constructor() {
+		this.privateMethod(this.privateField);
+		this.privateMethod(this.publicField);
+
+		this['privateMethod'](this.privateField);
+	}
+
+	//@ts-ignore
+	@decorator private privateMethod(a: string | number): void { }
+}
+
+function decorator(target: any, propertyKey: string): void {}
diff --git a/tests/test-cases/private-with-decorators/output.js b/tests/test-cases/private-with-decorators/output.js
new file mode 100644
index 0000000..88b2d55
--- /dev/null
+++ b/tests/test-cases/private-with-decorators/output.js
@@ -0,0 +1,29 @@
+"use strict";
+var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
+    var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+    if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+    else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+    return c > 3 && r && Object.defineProperty(target, key, r), r;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+var Class = /** @class */ (function () {
+    function Class() {
+        this.publicField = 123;
+        //@ts-ignore
+        this.privateField = 'string-value';
+        this.privateMethod(this.privateField);
+        this.privateMethod(this.publicField);
+        this['privateMethod'](this.privateField);
+    }
+    //@ts-ignore
+    Class.prototype.privateMethod = function (a) { };
+    __decorate([
+        decorator
+    ], Class.prototype, "privateField", void 0);
+    __decorate([
+        decorator
+    ], Class.prototype, "privateMethod", null);
+    return Class;
+}());
+exports.Class = Class;
+function decorator(target, propertyKey) { }