1 files changed, 96 insertions, 0 deletions
diff --git a/node_modules/babel-plugin-minify-simplify/lib/assignment-expression.js b/node_modules/babel-plugin-minify-simplify/lib/assignment-expression.js
new file mode 100644
index 00000000..3f9b0ce4
--- /dev/null
+++ b/node_modules/babel-plugin-minify-simplify/lib/assignment-expression.js
@@ -0,0 +1,96 @@
+"use strict";
+
+const operators = new Set(["+", "-", "*", "%", "<<", ">>", ">>>", "&", "|", "^", "/", "**"]);
+const updateOperators = new Set(["+", "-"]);
+
+module.exports = t => {
+  function simplify(path) {
+    const rightExpr = path.get("right");
+    const leftExpr = path.get("left");
+
+    if (path.node.operator !== "=") {
+      return;
+    }
+
+    const canBeUpdateExpression = 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"));
+
+      if (!leftPropNames || leftPropNames.indexOf(undefined) > -1 || !rightPropNames || rightPropNames.indexOf(undefined) > -1 || !operators.has(rightExpr.node.operator) || !areArraysEqual(leftPropNames, rightPropNames)) {
+        return;
+      }
+    } else {
+      if (!rightExpr.isBinaryExpression() || !operators.has(rightExpr.node.operator) || leftExpr.node.name !== rightExpr.node.left.name) {
+        return;
+      }
+    }
+
+    let newExpression; // special case x=x+1 --> ++x
+
+    if (canBeUpdateExpression) {
+      newExpression = t.updateExpression(rightExpr.node.operator + rightExpr.node.operator, t.clone(leftExpr.node), true
+      /* prefix */
+      );
+    } else {
+      newExpression = t.assignmentExpression(rightExpr.node.operator + "=", t.clone(leftExpr.node), t.clone(rightExpr.node.right));
+    }
+
+    path.replaceWith(newExpression);
+  }
+
+  return {
+    simplify
+  };
+};
+
+function areArraysEqual(arr1, arr2) {
+  return arr1.every((value, index) => {
+    return String(value) === String(arr2[index]);
+  });
+}
+
+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 === "MemberExpression") {
+    const node = obj.get("property").node;
+
+    if (node) {
+      propNames.push(getName(node));
+    }
+
+    obj = obj.get("object");
+  }
+
+  propNames.push(getName(obj.node));
+  return propNames;
+}
+
+function getName(node) {
+  if (node.type === "ThisExpression") {
+    return "this";
+  }
+
+  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
+
+
+  return node.name ? node.name + "_" : node.value
+  /* Literal */
+  ;
+}
+\ No newline at end of file