From c09dc38f0dc0e39725961570348e1a9b0a3bcc54 Mon Sep 17 00:00:00 2001
From: Corey Farrell <git@cfware.com>
Date: Wed, 24 Apr 2019 15:47:55 -0400
Subject: [PATCH] feat: Enable classProperties and classPrivateProperties
 parsers and coverage. (#379)

---
 .../src/instrumenter.js                       |  7 +--
 .../src/read-coverage.js                      | 10 +---
 .../istanbul-lib-instrument/src/visitor.js    |  6 +++
 .../test/specs/class-properties.yaml          | 49 +++++++++++++++++++
 .../test/util/guards.js                       |  8 +++
 5 files changed, 67 insertions(+), 13 deletions(-)
 create mode 100644 packages/istanbul-lib-instrument/test/specs/class-properties.yaml

diff --git a/packages/istanbul-lib-instrument/src/instrumenter.js b/packages/istanbul-lib-instrument/src/instrumenter.js
index 628e702c..5df1e728 100644
--- a/packages/istanbul-lib-instrument/src/instrumenter.js
+++ b/packages/istanbul-lib-instrument/src/instrumenter.js
@@ -26,11 +26,8 @@ export function defaultOpts() {
         plugins: [
             'asyncGenerators',
             'bigInt',
-            /* Verify and add upon release of node.js 12:
-             * classProperties
-             * classPrivateProperties
-             * classPrivateMethods
-             */
+            'classProperties',
+            'classPrivateProperties',
             'dynamicImport',
             'importMeta',
             'objectRestSpread',
diff --git a/packages/istanbul-lib-instrument/src/read-coverage.js b/packages/istanbul-lib-instrument/src/read-coverage.js
index 64a1b1a7..c0cd554f 100644
--- a/packages/istanbul-lib-instrument/src/read-coverage.js
+++ b/packages/istanbul-lib-instrument/src/read-coverage.js
@@ -2,6 +2,7 @@ import { parse } from '@babel/parser';
 import traverse from '@babel/traverse';
 import * as t from '@babel/types';
 import { MAGIC_KEY, MAGIC_VALUE } from './constants';
+import { defaultOpts } from './instrumenter';
 
 export default function readInitialCoverage(code) {
     if (typeof code !== 'string') {
@@ -14,14 +15,7 @@ export default function readInitialCoverage(code) {
         allowReturnOutsideFunction: true,
         allowSuperOutsideMethod: true,
         sourceType: 'script',
-        plugins: [
-            'asyncGenerators',
-            'dynamicImport',
-            'objectRestSpread',
-            'optionalCatchBinding',
-            'flow',
-            'jsx'
-        ]
+        plugins: defaultOpts().plugins
     });
 
     let covScope;
diff --git a/packages/istanbul-lib-instrument/src/visitor.js b/packages/istanbul-lib-instrument/src/visitor.js
index 8868d45b..4b8b513d 100644
--- a/packages/istanbul-lib-instrument/src/visitor.js
+++ b/packages/istanbul-lib-instrument/src/visitor.js
@@ -356,6 +356,10 @@ function coverVariableDeclarator(path) {
     this.insertStatementCounter(path.get('init'));
 }
 
+function coverClassPropDeclarator(path) {
+    this.insertStatementCounter(path.get('value'));
+}
+
 function makeBlock(path) {
     const T = this.types;
     if (!path.node) {
@@ -485,6 +489,8 @@ const codeVisitor = {
     ExportNamedDeclaration: entries(), // ignore processing only
     ClassMethod: entries(coverFunction),
     ClassDeclaration: entries(parenthesizedExpressionProp('superClass')),
+    ClassProperty: entries(coverClassPropDeclarator),
+    ClassPrivateProperty: entries(coverClassPropDeclarator),
     ObjectMethod: entries(coverFunction),
     ExpressionStatement: entries(coverStatement),
     BreakStatement: entries(coverStatement),
diff --git a/packages/istanbul-lib-instrument/test/specs/class-properties.yaml b/packages/istanbul-lib-instrument/test/specs/class-properties.yaml
new file mode 100644
index 00000000..2b109585
--- /dev/null
+++ b/packages/istanbul-lib-instrument/test/specs/class-properties.yaml
@@ -0,0 +1,49 @@
+---
+name: class property declaration
+guard: isClassPropAvailable
+code: |
+  class Foo {
+    bar = 1;
+    uninitialized;
+  }
+  output = args === 1 ? new Foo().bar : args
+tests:
+  - name: covered
+    args: 1
+    out: 1
+    lines: {'2': 1, '5': 1}
+    statements: {'0': 1, '1': 1}
+    branches: {'0': [1, 0]}
+    functions: {}
+  - name: not covered
+    args: 2
+    out: 2
+    lines: {'2': 0, '5': 1}
+    statements: {'0': 0, '1': 1}
+    branches: {'0': [0, 1]}
+    functions: {}
+---
+name: class private property declaration
+guard: isClassPrivatePropAvailable
+code: |
+  class Foo {
+    #bar = 1;
+    get bar() { return this.#bar; }
+    #uninitialized;
+  }
+  output = args === 1 ? new Foo().bar : args
+tests:
+  - name: covered
+    args: 1
+    out: 1
+    lines: {'2': 1, '3': 1, '6': 1}
+    statements: {'0': 1, '1': 1, '2': 1}
+    branches: {'0': [1, 0]}
+    functions: {'0': 1}
+  - name: not covered
+    args: 2
+    out: 2
+    lines: {'2': 0, '3': 0, '6': 1}
+    statements: {'0': 0, '1': 0, '2': 1}
+    branches: {'0': [0, 1]}
+    functions: {'0': 0}
diff --git a/packages/istanbul-lib-instrument/test/util/guards.js b/packages/istanbul-lib-instrument/test/util/guards.js
index cb2026a0..4b891e19 100644
--- a/packages/istanbul-lib-instrument/test/util/guards.js
+++ b/packages/istanbul-lib-instrument/test/util/guards.js
@@ -18,6 +18,14 @@ export function isYieldAvailable() {
     return tryThis('function *foo() { yield 1; }', 'yield');
 }
 
+export function isClassPropAvailable() {
+    return tryThis('class Foo { a = 1; }', 'class property');
+}
+
+export function isClassPrivatePropAvailable() {
+    return tryThis('class Foo { #a = 1; }', 'class private property');
+}
+
 export function isForOfAvailable() {
     return tryThis(
         'function *foo() { yield 1; }\n' + 'for (var k of foo()) {}',