remove object keys check to improve performance

babel · Jan 5, 2018 · 5a9b411 · 5a9b411
1 parent 4a27059
commit 5a9b411
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Showing 3 changed files with 29 additions and 5 deletions.
diff --git a/packages/babel-plugin-minify-simplify/src/conditional-expression.js b/packages/babel-plugin-minify-simplify/src/conditional-expression.js
@@ -13,7 +13,7 @@ module.exports = t => {
     const consequent = path.get("consequent");
     const alternate = path.get("alternate");
 
-    const EX = Symbol("Expression");
+    const { Expression: EX } = h.typeSymbols(t);
 
     // Convention:
     // ===============

diff --git a/packages/babel-plugin-minify-simplify/src/helpers.js b/packages/babel-plugin-minify-simplify/src/helpers.js
@@ -1,9 +1,29 @@
 "use strict";
 
+// Types as Symbols - for comparing types
+const types = {};
+// This is a test key which is used to avoid Object.keys check
+// Object.keys() check is really expensive
+// https://gist.github.com/vigneshshanmugam/c766550ecd02292dcdfbf0bf013b9d3d
+const testKey = "Expression";
+
+const typeSymbols = t => {
+  // don't recompute
+  if (types[testKey] !== undefined) {
+    return types;
+  }
+  t.TYPES.forEach(type => {
+    types[type] = Symbol.for(type);
+  });
+  return types;
+};
+
 const VOID_0 = t => t.unaryExpression("void", t.numericLiteral(0), true);
 
-const isExpression = (t, node, typeSymbol) =>
-  typeof typeSymbol !== "symbol" ? false : t.isExpression(node);
+const isNodeOfType = (t, node, typeSymbol) =>
+  typeof typeSymbol !== "symbol"
+    ? false
+    : t["is" + Symbol.keyFor(typeSymbol)](node);
 
 const isPatternMatchesPath = t =>
   function _isPatternMatchesPath(patternValue, inputPath) {
@@ -18,13 +38,17 @@ const isPatternMatchesPath = t =>
     if (typeof patternValue === "function") {
       return patternValue(inputPath);
     }
-    if (isExpression(t, inputPath.node, patternValue)) return true;
+    if (isNodeOfType(t, inputPath.node, patternValue)) return true;
     const evalResult = inputPath.evaluate();
     if (!evalResult.confident || !inputPath.isPure()) return false;
     return evalResult.value === patternValue;
   };
 
 module.exports = {
+  // Types as Symbols
+  typeSymbols,
+  // This is required for resolving type aliases
+  isNodeOfType,
   VOID_0,
   isPatternMatchesPath
 };
diff --git a/packages/babel-plugin-minify-simplify/src/logical-expression.js b/packages/babel-plugin-minify-simplify/src/logical-expression.js
@@ -40,7 +40,7 @@ module.exports = t => {
       return evalResult.confident && input.isPure() && !evalResult.value;
     };
 
-    const EX = Symbol("Expression");
+    const { Expression: EX } = h.typeSymbols(t);
 
     // Convention:
     // [left, operator, right, handler(leftNode, rightNode)]