From 3344baac195e00ee03280033cf70755d5c3924ab Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 27 Oct 2016 14:50:59 -0400
Subject: [PATCH 01/15] Simplify assignments to same identifier

---
 .../__tests__/simplify-test.js                | 48 +++++++++++++++++
 .../babel-plugin-minify-simplify/src/index.js | 53 +++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index d9f607848..d20535b12 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2136,4 +2136,52 @@ describe("simplify-plugin", () => {
     const expected = source;
     expect(transform(source)).toBe(expected);
   });
+
+  it("should transform assignments to the same identifier", () => {
+    const source = unpad(`
+      x = x + 1;
+      x = x - 1;
+      x = x * 1;
+      x = x % 1;
+      x = x << 1;
+      x = x >> 1;
+      x = x >>> 1;
+      x = x & 1;
+      x = x | 1;
+      x = x ^ 1;
+      x = x / 1;
+      x = x ** 1;
+      foo = foo + bar;
+      foo = foo * function(){};
+      foo += 123;
+      foo = 1 + foo;
+      x = x = x + 1;
+      foo = foo + bar + baz;
+      window.foo = window.foo + 1;
+      window.foo.bar = window.foo.baz + 1;
+    `);
+    const expected = unpad(`
+      x++,
+      x--,
+      x *= 1,
+      x %= 1,
+      x <<= 1,
+      x >>= 1,
+      x >>>= 1,
+      x &= 1,
+      x |= 1,
+      x ^= 1,
+      x /= 1,
+      x **= 1,
+      foo += bar,
+      foo *= function () {},
+      foo += 123,
+      foo = 1 + foo,
+      x = x++,
+      foo = foo + bar + baz,
+      window.foo = window.foo + 1,
+      window.foo.bar = window.foo.baz + 1;
+    `);
+    expect(transform(source)).toBe(expected);
+  });
 });
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index a18d5d2de..04f6df991 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -28,6 +28,17 @@ module.exports = ({ types: t }) => {
   const or = (a, b) => t.logicalExpression("||", a, b);
   const and = (a, b) => t.logicalExpression("&&", a, b);
 
+  const operators = new Set([
+    '+', '-', '*', '%',
+    '<<', '>>', '>>>',
+    '&', '|', '^', '/',
+    '**'
+  ]);
+
+  const updateOperators = new Set([
+    '+', '-'
+  ]);
+
   return {
     name: "minify-simplify",
     visitor: {
@@ -124,6 +135,48 @@ module.exports = ({ types: t }) => {
         ],
       },
 
+      AssignmentExpression(path) {
+
+        const right = path.get('right');
+        const left = path.get('left');
+
+        const canShorten = (
+          right.type === 'BinaryExpression' &&
+          operators.has(right.node.operator) &&
+          left.node.name === right.node.left.name
+        );
+
+		    if (!canShorten) return;
+
+        const canBeUpdateExpression = (
+          right.node.right.type === 'NumericLiteral' &&
+          right.node.right.value === 1 &&
+          updateOperators.has(right.node.operator));
+
+        if (left.node.name === undefined) {
+          // not an identifier, probably MemberExpression which we don't transform yet
+          return;
+        }
+
+        if (canBeUpdateExpression) {
+
+          const newExpression = t.updateExpression(
+            right.node.operator + right.node.operator,
+            t.identifier(left.node.name));
+
+          path.replaceWith(newExpression);
+        }
+        else {
+
+          const newExpression = t.assignmentExpression(
+            right.node.operator + '=',
+            t.identifier(left.node.name),
+            t.clone(right.node.right));
+
+          path.replaceWith(newExpression);
+        }
+      },
+
       ConditionalExpression: {
         enter: [
           // !foo ? 'foo' : 'bar' -> foo ? 'bar' : 'foo'

From a4d10bc6e83da853ca2231065e6c0d1c9bbd8e6a Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 27 Oct 2016 14:57:18 -0400
Subject: [PATCH 02/15] Add tests

---
 .../__tests__/simplify-test.js                | 95 ++++++++++---------
 .../babel-plugin-minify-simplify/src/index.js |  3 +-
 2 files changed, 52 insertions(+), 46 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index d20535b12..f9ce1649a 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2138,50 +2138,55 @@ describe("simplify-plugin", () => {
   });
 
   it("should transform assignments to the same identifier", () => {
-    const source = unpad(`
-      x = x + 1;
-      x = x - 1;
-      x = x * 1;
-      x = x % 1;
-      x = x << 1;
-      x = x >> 1;
-      x = x >>> 1;
-      x = x & 1;
-      x = x | 1;
-      x = x ^ 1;
-      x = x / 1;
-      x = x ** 1;
-      foo = foo + bar;
-      foo = foo * function(){};
-      foo += 123;
-      foo = 1 + foo;
-      x = x = x + 1;
-      foo = foo + bar + baz;
-      window.foo = window.foo + 1;
-      window.foo.bar = window.foo.baz + 1;
-    `);
-    const expected = unpad(`
-      x++,
-      x--,
-      x *= 1,
-      x %= 1,
-      x <<= 1,
-      x >>= 1,
-      x >>>= 1,
-      x &= 1,
-      x |= 1,
-      x ^= 1,
-      x /= 1,
-      x **= 1,
-      foo += bar,
-      foo *= function () {},
-      foo += 123,
-      foo = 1 + foo,
-      x = x++,
-      foo = foo + bar + baz,
-      window.foo = window.foo + 1,
-      window.foo.bar = window.foo.baz + 1;
-    `);
-    expect(transform(source)).toBe(expected);
+
+    const actual = [
+      'x = x + 1;',
+      'x = x - 1;',
+      'x = x * 1;',
+      'x = x % 1;',
+      'x = x << 1;',
+      'x = x >> 1;',
+      'x = x >>> 1;',
+      'x = x & 1;',
+      'x = x | 1;',
+      'x = x ^ 1;',
+      'x = x / 1;',
+      'x = x ** 1;',
+      'foo = foo + bar;',
+      'foo = foo * function(){};',
+      'foo += 123;',
+      'foo = 1 + foo;',
+      'x = x = x + 1;',
+      'foo = foo + bar + baz;',
+      'window.foo = window.foo + 1;',
+      'window.foo.bar = window.foo.baz + 1;',
+    ];
+
+    const expected = [
+      'x++;',
+      'x--;',
+      'x *= 1;',
+      'x %= 1;',
+      'x <<= 1;',
+      'x >>= 1;',
+      'x >>>= 1;',
+      'x &= 1;',
+      'x |= 1;',
+      'x ^= 1;',
+      'x /= 1;',
+      'x **= 1;',
+      'foo += bar;',
+      'foo *= function () {};',
+      'foo += 123;',
+      'foo = 1 + foo;',
+      'x = x++;',
+      'foo = foo + bar + baz;',
+      'window.foo = window.foo + 1;',
+      'window.foo.bar = window.foo.baz + 1;',
+    ];
+
+    actual.forEach((test, index) => {
+      expect(transform(test)).toBe(expected[index]);
+    });
   });
 });
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index 04f6df991..b0095d6a5 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -154,7 +154,8 @@ module.exports = ({ types: t }) => {
           updateOperators.has(right.node.operator));
 
         if (left.node.name === undefined) {
-          // not an identifier, probably MemberExpression which we don't transform yet
+          // TODO: transform MemberExpressions as well
+          // e.g. foo.bar = foo.bar + 123;
           return;
         }
 

From c666da10e995c28d3fac93b2ca57dfabc5168de6 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 27 Oct 2016 14:58:00 -0400
Subject: [PATCH 03/15] Bump versions

---
 packages/babel-plugin-minify-simplify/package.json | 2 +-
 packages/babel-preset-babili/package.json          | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/package.json b/packages/babel-plugin-minify-simplify/package.json
index deeffe27d..c7a0ab7ad 100644
--- a/packages/babel-plugin-minify-simplify/package.json
+++ b/packages/babel-plugin-minify-simplify/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-minify-simplify",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "description": "",
   "homepage": "https://github.com/babel/babili#readme",
   "repository": "https://github.com/babel/babili/tree/master/packages/babel-plugin-minify-simplify",
diff --git a/packages/babel-preset-babili/package.json b/packages/babel-preset-babili/package.json
index 362a45502..fa9f0db26 100644
--- a/packages/babel-preset-babili/package.json
+++ b/packages/babel-preset-babili/package.json
@@ -20,7 +20,7 @@
     "babel-plugin-minify-mangle-names": "^0.0.3",
     "babel-plugin-minify-numeric-literals": "^0.0.1",
     "babel-plugin-minify-replace": "^0.0.1",
-    "babel-plugin-minify-simplify": "^0.0.3",
+    "babel-plugin-minify-simplify": "^0.0.4",
     "babel-plugin-minify-type-constructors": "^0.0.1",
     "babel-plugin-transform-member-expression-literals": "^6.8.0",
     "babel-plugin-transform-merge-sibling-variables": "^6.8.0",

From c6ec99d7e34882eac99ed201fca800c4dc16d217 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 27 Oct 2016 15:03:48 -0400
Subject: [PATCH 04/15] Remove versioning

---
 packages/babel-preset-babili/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babel-preset-babili/package.json b/packages/babel-preset-babili/package.json
index fa9f0db26..362a45502 100644
--- a/packages/babel-preset-babili/package.json
+++ b/packages/babel-preset-babili/package.json
@@ -20,7 +20,7 @@
     "babel-plugin-minify-mangle-names": "^0.0.3",
     "babel-plugin-minify-numeric-literals": "^0.0.1",
     "babel-plugin-minify-replace": "^0.0.1",
-    "babel-plugin-minify-simplify": "^0.0.4",
+    "babel-plugin-minify-simplify": "^0.0.3",
     "babel-plugin-minify-type-constructors": "^0.0.1",
     "babel-plugin-transform-member-expression-literals": "^6.8.0",
     "babel-plugin-transform-merge-sibling-variables": "^6.8.0",

From 6b913fe007af4c20510067a9922adc282fee47df Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 27 Oct 2016 16:46:21 -0400
Subject: [PATCH 05/15] Remove version

---
 packages/babel-plugin-minify-simplify/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babel-plugin-minify-simplify/package.json b/packages/babel-plugin-minify-simplify/package.json
index c7a0ab7ad..deeffe27d 100644
--- a/packages/babel-plugin-minify-simplify/package.json
+++ b/packages/babel-plugin-minify-simplify/package.json
@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-minify-simplify",
-  "version": "0.0.4",
+  "version": "0.0.3",
   "description": "",
   "homepage": "https://github.com/babel/babili#readme",
   "repository": "https://github.com/babel/babili/tree/master/packages/babel-plugin-minify-simplify",

From c1aa0caf98e7ec4ff339777cb9240019ad13a3c4 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Mon, 31 Oct 2016 20:50:23 -0400
Subject: [PATCH 06/15] Add support for optimizing member expressions

---
 .../__tests__/simplify-test.js                | 167 ++++++++++++------
 .../babel-plugin-minify-simplify/src/index.js | 111 +++++++++---
 2 files changed, 199 insertions(+), 79 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index f9ce1649a..4450e4f03 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2137,56 +2137,121 @@ describe("simplify-plugin", () => {
     expect(transform(source)).toBe(expected);
   });
 
-  it("should transform assignments to the same identifier", () => {
-
-    const actual = [
-      'x = x + 1;',
-      'x = x - 1;',
-      'x = x * 1;',
-      'x = x % 1;',
-      'x = x << 1;',
-      'x = x >> 1;',
-      'x = x >>> 1;',
-      'x = x & 1;',
-      'x = x | 1;',
-      'x = x ^ 1;',
-      'x = x / 1;',
-      'x = x ** 1;',
-      'foo = foo + bar;',
-      'foo = foo * function(){};',
-      'foo += 123;',
-      'foo = 1 + foo;',
-      'x = x = x + 1;',
-      'foo = foo + bar + baz;',
-      'window.foo = window.foo + 1;',
-      'window.foo.bar = window.foo.baz + 1;',
-    ];
-
-    const expected = [
-      'x++;',
-      'x--;',
-      'x *= 1;',
-      'x %= 1;',
-      'x <<= 1;',
-      'x >>= 1;',
-      'x >>>= 1;',
-      'x &= 1;',
-      'x |= 1;',
-      'x ^= 1;',
-      'x /= 1;',
-      'x **= 1;',
-      'foo += bar;',
-      'foo *= function () {};',
-      'foo += 123;',
-      'foo = 1 + foo;',
-      'x = x++;',
-      'foo = foo + bar + baz;',
-      'window.foo = window.foo + 1;',
-      'window.foo.bar = window.foo.baz + 1;',
-    ];
-
-    actual.forEach((test, index) => {
-      expect(transform(test)).toBe(expected[index]);
-    });
+  it("should simplify assignments", () => {
+
+    const source = unpad(`
+      x = x + 1,
+      x = x - 1,
+      x = x * 1,
+      x = x % 1,
+      x = x << 1,
+      x = x >> 1,
+      x = x >>> 1,
+      x = x & 1,
+      x = x | 1,
+      x = x ^ 1,
+      x = x / 1,
+      x = x ** 1;
+    `);
+    const expected = unpad(`
+      x++,
+      x--,
+      x *= 1,
+      x %= 1,
+      x <<= 1,
+      x >>= 1,
+      x >>>= 1,
+      x &= 1,
+      x |= 1,
+      x ^= 1,
+      x /= 1,
+      x **= 1;
+    `).replace(/\s+/g, ' ');
+
+    expect(transform(source)).toBe(expected);
+  });
+
+  it("should simplify assignments 2", () => {
+
+    const source = unpad(`
+      foo = foo + bar,
+      foo = foo * function(){},
+      foo += 123,
+      foo = 1 + foo,
+      x = x = x + 1,
+      foo = foo + bar + baz
+    `);
+    const expected = unpad(`
+      foo += bar,
+      foo *= function () {},
+      foo += 123,
+      foo = 1 + foo,
+      x = x++,
+      foo = foo + bar + baz;
+    `).replace(/\s+/g, ' ');
+
+    expect(transform(source)).toBe(expected);
+  });
+
+  it("should simplify assignments w. member expressions", () => {
+
+    const source = unpad(`
+      foo.bar = foo.bar + 1,
+      foo.bar = foo.bar + 2,
+      foo["x"] = foo[x] + 2,
+      foo[x] = foo[x] + 2,
+      foo[x] = foo["x"] + 2,
+      foo["x"] = foo["x"] + 2,
+      foo[1] = foo["1"] + 2,
+      foo["bar"] = foo["bar"] + 2,
+      foo[bar()] = foo[bar()] + 2,
+      foo[""] = foo[""] + 2,
+      foo[2] = foo[2] + 2,
+      foo[{}] = foo[{}] + 1,
+      foo[function(){}] = foo[function(){}] + 1,
+      foo[false] = foo[false] + 1,
+      foo.bar.baz = foo.bar.baz + 321,
+      this.hello = this.hello + 1;
+    `);
+    const expected = unpad(`
+      foo.bar++,
+      foo.bar += 2,
+      foo["x"] = foo[x] + 2,
+      foo[x] += 2,
+      foo[x] = foo["x"] + 2,
+      foo["x"] += 2,
+      foo[1] += 2,
+      foo["bar"] += 2,
+      foo[bar()] = foo[bar()] + 2,
+      foo[""] += 2,
+      foo[2] += 2,
+      foo[{}] = foo[{}] + 1,
+      foo[function () {}] = foo[function () {}] + 1,
+      foo[false]++,
+      foo.bar.baz += 321,
+      this.hello++;
+    `).replace(/\s+/g, ' ');
+
+    expect(transform(source)).toBe(expected);
+  });
+
+  it("should simplify assignments w. member expressions", () => {
+
+    const source = unpad(`
+      class Foo {
+        foo() {
+          super.foo = super.foo + 1;
+        }
+      };
+    `);
+    const expected = unpad(`
+      class Foo {
+        foo() {
+          super.foo++;
+        }
+      };
+    `);
+
+    expect(transform(source)).toBe(expected);
   });
 });
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index b0095d6a5..ee9d8b85c 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -39,6 +39,51 @@ module.exports = ({ types: t }) => {
     '+', '-'
   ]);
 
+  function isEqual(arr1, arr2) {
+    return arr1.every((value, index) => {
+      return value.toString() === arr2[index].toString();
+    });
+  }
+
+  function getName(node) {
+    if (node.type === 'ThisExpression') {
+      return 'this';
+    }
+    if (node.type === 'Super') {
+      return 'super';
+    }
+    // augment identifiers so that they don't match
+    // string/number literals
+    // but still match against each other
+    return node.name
+      ? node.name + '_'
+    	: node.value /* Literal */;
+  }
+
+  function getPropNames(path) {
+    if (!path.isMemberExpression()) {
+      return;
+    }
+
+    let obj = path.get('object');
+
+    const prop = path.get('property');
+    const propNames = [getName(prop.node)];
+
+    while (obj.type !== 'Identifier' &&
+           obj.type !== 'ThisExpression' &&
+           obj.type !== 'Super') {
+      const node = obj.get('property').node;
+      if (node) {
+        propNames.push(getName(node));
+      }
+      obj = obj.get('object');
+    }
+    propNames.push(getName(obj.node));
+
+    return propNames;
+  }
+
   return {
     name: "minify-simplify",
     visitor: {
@@ -137,45 +182,55 @@ module.exports = ({ types: t }) => {
 
       AssignmentExpression(path) {
 
-        const right = path.get('right');
-        const left = path.get('left');
-
-        const canShorten = (
-          right.type === 'BinaryExpression' &&
-          operators.has(right.node.operator) &&
-          left.node.name === right.node.left.name
-        );
-
-		    if (!canShorten) return;
+        const rightExpr = path.get('right');
+        const leftExpr = path.get('left');
 
         const canBeUpdateExpression = (
-          right.node.right.type === 'NumericLiteral' &&
-          right.node.right.value === 1 &&
-          updateOperators.has(right.node.operator));
+          rightExpr.get('right').isNumericLiteral() &&
+          rightExpr.get('right').node.value === 1 &&
+          updateOperators.has(rightExpr.node.operator));
 
-        if (left.node.name === undefined) {
-          // TODO: transform MemberExpressions as well
-          // e.g. foo.bar = foo.bar + 123;
-          return;
-        }
+        if (leftExpr.isMemberExpression()) {
 
-        if (canBeUpdateExpression) {
+          const leftPropNames = getPropNames(leftExpr);
+          const rightPropNames = getPropNames(rightExpr.get('left'));
 
-          const newExpression = t.updateExpression(
-            right.node.operator + right.node.operator,
-            t.identifier(left.node.name));
+          if (!leftPropNames ||
+              leftPropNames.includes(undefined) ||
+              !rightPropNames ||
+              rightPropNames.includes(undefined) ||
+             !isEqual(leftPropNames, rightPropNames)) {
+            return;
+          }
 
-          path.replaceWith(newExpression);
+          // TODO: implement replacement
         }
         else {
+          if (!rightExpr.isBinaryExpression() ||
+              !operators.has(rightExpr.node.operator) ||
+              leftExpr.node.name !== rightExpr.node.left.name) {
+          	return;
+          }
+        }
 
-          const newExpression = t.assignmentExpression(
-            right.node.operator + '=',
-            t.identifier(left.node.name),
-            t.clone(right.node.right));
+        let newExpression;
 
-          path.replaceWith(newExpression);
+        // special case +=1 --> ++
+        if (canBeUpdateExpression) {
+          newExpression = t.updateExpression(
+            rightExpr.node.operator + rightExpr.node.operator,
+            leftExpr.isMemberExpression()
+              ? t.clone(leftExpr.node)
+              : t.identifier(leftExpr.node.name));
         }
+        else {
+          newExpression = t.assignmentExpression(
+            rightExpr.node.operator + '=',
+            t.clone(leftExpr.node),
+            t.clone(rightExpr.node.right));
+        }
+
+        path.replaceWith(newExpression);
       },
 
       ConditionalExpression: {

From 6dfe2186a3abee90ad7a0af0b5b774dbf6690d38 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Mon, 31 Oct 2016 20:51:36 -0400
Subject: [PATCH 07/15] Fix test name

---
 .../babel-plugin-minify-simplify/__tests__/simplify-test.js     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index 4450e4f03..17b1487d7 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2235,7 +2235,7 @@ describe("simplify-plugin", () => {
     expect(transform(source)).toBe(expected);
   });
 
-  it("should simplify assignments w. member expressions", () => {
+  it("should simplify assignments w. super", () => {
 
     const source = unpad(`
       class Foo {

From 6813842a55fccf4ee044b2bcc0858ff752fe95c2 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Mon, 31 Oct 2016 20:55:09 -0400
Subject: [PATCH 08/15] Remove comment

---
 packages/babel-plugin-minify-simplify/src/index.js | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index ee9d8b85c..c96147869 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -202,8 +202,6 @@ module.exports = ({ types: t }) => {
              !isEqual(leftPropNames, rightPropNames)) {
             return;
           }
-
-          // TODO: implement replacement
         }
         else {
           if (!rightExpr.isBinaryExpression() ||

From 5ddc5f8b70672969f59ddb1f2f97c25545b06306 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Mon, 31 Oct 2016 20:55:54 -0400
Subject: [PATCH 09/15] Simplify ternary

---
 packages/babel-plugin-minify-simplify/src/index.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index c96147869..c04557cf4 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -217,9 +217,7 @@ module.exports = ({ types: t }) => {
         if (canBeUpdateExpression) {
           newExpression = t.updateExpression(
             rightExpr.node.operator + rightExpr.node.operator,
-            leftExpr.isMemberExpression()
-              ? t.clone(leftExpr.node)
-              : t.identifier(leftExpr.node.name));
+            t.clone(leftExpr.node));
         }
         else {
           newExpression = t.assignmentExpression(

From 2c7a0d57a63fd3a24cfc1e0e9d382cfb29ce8476 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Tue, 1 Nov 2016 19:20:59 -0400
Subject: [PATCH 10/15] Fix bugs, simplify check

---
 .../__tests__/simplify-test.js                   | 16 ++++++++++++++--
 .../babel-plugin-minify-simplify/src/index.js    |  9 +++++----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index 17b1487d7..ea8bbf640 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2211,8 +2211,11 @@ describe("simplify-plugin", () => {
       foo[function(){}] = foo[function(){}] + 1,
       foo[false] = foo[false] + 1,
       foo.bar.baz = foo.bar.baz + 321,
-      this.hello = this.hello + 1;
+      this.hello = this.hello + 1,
+      foo[null] = foo[null] + 1,
+      foo[undefined] = foo[undefined] + 1;
     `);
+    // TODO: foo[void 0] = foo[void 0] + 1;
     const expected = unpad(`
       foo.bar++,
       foo.bar += 2,
@@ -2229,7 +2232,9 @@ describe("simplify-plugin", () => {
       foo[function () {}] = foo[function () {}] + 1,
       foo[false]++,
       foo.bar.baz += 321,
-      this.hello++;
+      this.hello++,
+      foo[null]++,
+      foo[undefined]++;
     `).replace(/\s+/g, ' ');
 
     expect(transform(source)).toBe(expected);
@@ -2254,4 +2259,11 @@ describe("simplify-plugin", () => {
 
     expect(transform(source)).toBe(expected);
   });
+
+  it("should not simplify assignments w. template literals", () => {
+
+    const source = unpad('foo[`x`] = foo[`x`] + 1;');
+
+    expect(transform(source)).toBe(source);
+  });
 });
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index c04557cf4..e5f3286b5 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -41,7 +41,7 @@ module.exports = ({ types: t }) => {
 
   function isEqual(arr1, arr2) {
     return arr1.every((value, index) => {
-      return value.toString() === arr2[index].toString();
+      return String(value) === String(arr2[index]);
     });
   }
 
@@ -52,6 +52,9 @@ module.exports = ({ types: t }) => {
     if (node.type === 'Super') {
       return 'super';
     }
+    if (node.type === 'NullLiteral') {
+      return 'null';
+    }
     // augment identifiers so that they don't match
     // string/number literals
     // but still match against each other
@@ -70,9 +73,7 @@ module.exports = ({ types: t }) => {
     const prop = path.get('property');
     const propNames = [getName(prop.node)];
 
-    while (obj.type !== 'Identifier' &&
-           obj.type !== 'ThisExpression' &&
-           obj.type !== 'Super') {
+    while (obj.type === 'MemberExpression') {
       const node = obj.get('property').node;
       if (node) {
         propNames.push(getName(node));

From 4f7e8ebf3c46dc41a5e855c2a9a01a2e52198342 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Tue, 1 Nov 2016 19:27:02 -0400
Subject: [PATCH 11/15] Change postfix to prefix

---
 .../__tests__/simplify-test.js                 | 18 +++++++++---------
 .../babel-plugin-minify-simplify/src/index.js  |  5 +++--
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index ea8bbf640..0ccc579fc 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2154,8 +2154,8 @@ describe("simplify-plugin", () => {
       x = x ** 1;
     `);
     const expected = unpad(`
-      x++,
-      x--,
+      ++x,
+      --x,
       x *= 1,
       x %= 1,
       x <<= 1,
@@ -2186,7 +2186,7 @@ describe("simplify-plugin", () => {
       foo *= function () {},
       foo += 123,
       foo = 1 + foo,
-      x = x++,
+      x = ++x,
       foo = foo + bar + baz;
     `).replace(/\s+/g, ' ');
 
@@ -2217,7 +2217,7 @@ describe("simplify-plugin", () => {
     `);
     // TODO: foo[void 0] = foo[void 0] + 1;
     const expected = unpad(`
-      foo.bar++,
+      ++foo.bar,
       foo.bar += 2,
       foo["x"] = foo[x] + 2,
       foo[x] += 2,
@@ -2230,11 +2230,11 @@ describe("simplify-plugin", () => {
       foo[2] += 2,
       foo[{}] = foo[{}] + 1,
       foo[function () {}] = foo[function () {}] + 1,
-      foo[false]++,
+      ++foo[false],
       foo.bar.baz += 321,
-      this.hello++,
-      foo[null]++,
-      foo[undefined]++;
+      ++this.hello,
+      ++foo[null],
+      ++foo[undefined];
     `).replace(/\s+/g, ' ');
 
     expect(transform(source)).toBe(expected);
@@ -2252,7 +2252,7 @@ describe("simplify-plugin", () => {
     const expected = unpad(`
       class Foo {
         foo() {
-          super.foo++;
+          ++super.foo;
         }
       };
     `);
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index e5f3286b5..ad8911832 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -214,11 +214,12 @@ module.exports = ({ types: t }) => {
 
         let newExpression;
 
-        // special case +=1 --> ++
+        // special case x=x+1 --> ++x
         if (canBeUpdateExpression) {
           newExpression = t.updateExpression(
             rightExpr.node.operator + rightExpr.node.operator,
-            t.clone(leftExpr.node));
+            t.clone(leftExpr.node),
+            true /* prefix */);
         }
         else {
           newExpression = t.assignmentExpression(

From 8c0a456a0076600fb0b6c1652c90903c8dcd5304 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Thu, 10 Nov 2016 12:06:41 -0800
Subject: [PATCH 12/15] Exclude operators for member expressions too

---
 .../babel-plugin-minify-simplify/__tests__/simplify-test.js | 6 ++++--
 packages/babel-plugin-minify-simplify/src/index.js          | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index 0b59000b3..5b6ee5359 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2429,7 +2429,8 @@ describe("simplify-plugin", () => {
       foo.bar.baz = foo.bar.baz + 321,
       this.hello = this.hello + 1,
       foo[null] = foo[null] + 1,
-      foo[undefined] = foo[undefined] + 1;
+      foo[undefined] = foo[undefined] + 1,
+      foo.bar = foo.bar || {};
     `);
     // TODO: foo[void 0] = foo[void 0] + 1;
     const expected = unpad(`
@@ -2450,7 +2451,8 @@ describe("simplify-plugin", () => {
       foo.bar.baz += 321,
       ++this.hello,
       ++foo[null],
-      ++foo[undefined];
+      ++foo[undefined],
+      foo.bar = foo.bar || {};
     `).replace(/\s+/g, ' ');
 
     expect(transform(source)).toBe(expected);
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index 963981615..89812a156 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -269,7 +269,8 @@ module.exports = ({ types: t }) => {
               leftPropNames.includes(undefined) ||
               !rightPropNames ||
               rightPropNames.includes(undefined) ||
-             !isEqual(leftPropNames, rightPropNames)) {
+              !operators.has(rightExpr.node.operator) ||
+              !isEqual(leftPropNames, rightPropNames)) {
             return;
           }
         }

From 6eaded6f83f1b136e87afa1d60afa934a7fe80ed Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Fri, 11 Nov 2016 14:32:16 -0800
Subject: [PATCH 13/15] includes -> indexOf

---
 packages/babel-plugin-minify-simplify/src/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index 89812a156..22f3f7192 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -266,9 +266,9 @@ module.exports = ({ types: t }) => {
           const rightPropNames = getPropNames(rightExpr.get('left'));
 
           if (!leftPropNames ||
-              leftPropNames.includes(undefined) ||
+              leftPropNames.indexOf(undefined) > -1 ||
               !rightPropNames ||
-              rightPropNames.includes(undefined) ||
+              rightPropNames.indexOf(undefined) > -1 ||
               !operators.has(rightExpr.node.operator) ||
               !isEqual(leftPropNames, rightPropNames)) {
             return;

From edd236fc61697f025161439ecae9fce14a6b4534 Mon Sep 17 00:00:00 2001
From: Boopathi Rajaa <me@boopathi.in>
Date: Sat, 12 Nov 2016 00:10:46 +0100
Subject: [PATCH 14/15] Fix lint

---
 .../__tests__/simplify-test.js                |  8 +--
 .../babel-plugin-minify-simplify/src/index.js | 50 +++++++++----------
 .../src/index.js                              |  6 +--
 3 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
index 5b6ee5359..b57ba8ddc 100644
--- a/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
+++ b/packages/babel-plugin-minify-simplify/__tests__/simplify-test.js
@@ -2382,7 +2382,7 @@ describe("simplify-plugin", () => {
       x ^= 1,
       x /= 1,
       x **= 1;
-    `).replace(/\s+/g, ' ');
+    `).replace(/\s+/g, " ");
 
     expect(transform(source)).toBe(expected);
   });
@@ -2404,7 +2404,7 @@ describe("simplify-plugin", () => {
       foo = 1 + foo,
       x = ++x,
       foo = foo + bar + baz;
-    `).replace(/\s+/g, ' ');
+    `).replace(/\s+/g, " ");
 
     expect(transform(source)).toBe(expected);
   });
@@ -2453,7 +2453,7 @@ describe("simplify-plugin", () => {
       ++foo[null],
       ++foo[undefined],
       foo.bar = foo.bar || {};
-    `).replace(/\s+/g, ' ');
+    `).replace(/\s+/g, " ");
 
     expect(transform(source)).toBe(expected);
   });
@@ -2480,7 +2480,7 @@ describe("simplify-plugin", () => {
 
   it("should not simplify assignments w. template literals", () => {
 
-    const source = unpad('foo[`x`] = foo[`x`] + 1;');
+    const source = unpad("foo[`x`] = foo[`x`] + 1;");
 
     expect(transform(source)).toBe(source);
   });
diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index 22f3f7192..8340dedb6 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -29,14 +29,14 @@ module.exports = ({ types: t }) => {
   const and = (a, b) => t.logicalExpression("&&", a, b);
 
   const operators = new Set([
-    '+', '-', '*', '%',
-    '<<', '>>', '>>>',
-    '&', '|', '^', '/',
-    '**'
+    "+", "-", "*", "%",
+    "<<", ">>", ">>>",
+    "&", "|", "^", "/",
+    "**"
   ]);
 
   const updateOperators = new Set([
-    '+', '-'
+    "+", "-"
   ]);
 
   function isEqual(arr1, arr2) {
@@ -46,21 +46,21 @@ module.exports = ({ types: t }) => {
   }
 
   function getName(node) {
-    if (node.type === 'ThisExpression') {
-      return 'this';
+    if (node.type === "ThisExpression") {
+      return "this";
     }
-    if (node.type === 'Super') {
-      return 'super';
+    if (node.type === "Super") {
+      return "super";
     }
-    if (node.type === 'NullLiteral') {
-      return 'null';
+    if (node.type === "NullLiteral") {
+      return "null";
     }
     // augment identifiers so that they don't match
     // string/number literals
     // but still match against each other
     return node.name
-      ? node.name + '_'
-    	: node.value /* Literal */;
+      ? node.name + "_"
+      : node.value /* Literal */;
   }
 
   function getPropNames(path) {
@@ -68,17 +68,17 @@ module.exports = ({ types: t }) => {
       return;
     }
 
-    let obj = path.get('object');
+    let obj = path.get("object");
 
-    const prop = path.get('property');
+    const prop = path.get("property");
     const propNames = [getName(prop.node)];
 
-    while (obj.type === 'MemberExpression') {
-      const node = obj.get('property').node;
+    while (obj.type === "MemberExpression") {
+      const node = obj.get("property").node;
       if (node) {
         propNames.push(getName(node));
       }
-      obj = obj.get('object');
+      obj = obj.get("object");
     }
     propNames.push(getName(obj.node));
 
@@ -252,18 +252,18 @@ module.exports = ({ types: t }) => {
 
       AssignmentExpression(path) {
 
-        const rightExpr = path.get('right');
-        const leftExpr = path.get('left');
+        const rightExpr = path.get("right");
+        const leftExpr = path.get("left");
 
         const canBeUpdateExpression = (
-          rightExpr.get('right').isNumericLiteral() &&
-          rightExpr.get('right').node.value === 1 &&
+          rightExpr.get("right").isNumericLiteral() &&
+          rightExpr.get("right").node.value === 1 &&
           updateOperators.has(rightExpr.node.operator));
 
         if (leftExpr.isMemberExpression()) {
 
           const leftPropNames = getPropNames(leftExpr);
-          const rightPropNames = getPropNames(rightExpr.get('left'));
+          const rightPropNames = getPropNames(rightExpr.get("left"));
 
           if (!leftPropNames ||
               leftPropNames.indexOf(undefined) > -1 ||
@@ -278,7 +278,7 @@ module.exports = ({ types: t }) => {
           if (!rightExpr.isBinaryExpression() ||
               !operators.has(rightExpr.node.operator) ||
               leftExpr.node.name !== rightExpr.node.left.name) {
-          	return;
+            return;
           }
         }
 
@@ -293,7 +293,7 @@ module.exports = ({ types: t }) => {
         }
         else {
           newExpression = t.assignmentExpression(
-            rightExpr.node.operator + '=',
+            rightExpr.node.operator + "=",
             t.clone(leftExpr.node),
             t.clone(rightExpr.node.right));
         }
diff --git a/packages/babel-plugin-transform-regexp-constructors/src/index.js b/packages/babel-plugin-transform-regexp-constructors/src/index.js
index 29e62714a..9c7453bc2 100644
--- a/packages/babel-plugin-transform-regexp-constructors/src/index.js
+++ b/packages/babel-plugin-transform-regexp-constructors/src/index.js
@@ -23,9 +23,9 @@ module.exports = function({ types: t }) {
                       "";
 
         pattern = pattern
-          .replace(/\n/g, '\\n')
-          .replace(/\r/g, '\\r')
-          .replace(/\//g, '\\/');
+          .replace(/\n/g, "\\n")
+          .replace(/\r/g, "\\r")
+          .replace(/\//g, "\\/");
 
         path.replaceWith(t.regExpLiteral(pattern, flags));
       }

From b058bd0fc4783eaffb714ce080532829045b7854 Mon Sep 17 00:00:00 2001
From: Juriy Zaytsev <kangax@fb.com>
Date: Sun, 13 Nov 2016 12:26:00 -0800
Subject: [PATCH 15/15] Improve method name

---
 packages/babel-plugin-minify-simplify/src/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/babel-plugin-minify-simplify/src/index.js b/packages/babel-plugin-minify-simplify/src/index.js
index 8340dedb6..c2f4c52c4 100644
--- a/packages/babel-plugin-minify-simplify/src/index.js
+++ b/packages/babel-plugin-minify-simplify/src/index.js
@@ -39,7 +39,7 @@ module.exports = ({ types: t }) => {
     "+", "-"
   ]);
 
-  function isEqual(arr1, arr2) {
+  function areArraysEqual(arr1, arr2) {
     return arr1.every((value, index) => {
       return String(value) === String(arr2[index]);
     });
@@ -270,7 +270,7 @@ module.exports = ({ types: t }) => {
               !rightPropNames ||
               rightPropNames.indexOf(undefined) > -1 ||
               !operators.has(rightExpr.node.operator) ||
-              !isEqual(leftPropNames, rightPropNames)) {
+              !areArraysEqual(leftPropNames, rightPropNames)) {
             return;
           }
         }