[ts] Handle exponentiation operator in constant folding (#15418)

Emanuel Hoogeveen · web-flow · commit eb4dfe7b3c73 · 2023-02-12T19:05:04.000+01:00
diff --git a/packages/babel-plugin-transform-typescript/src/enum.ts b/packages/babel-plugin-transform-typescript/src/enum.ts
@@ -146,7 +146,7 @@ export function translateEnumValues(
     const initializer = member.initializer;
     let value: t.Expression;
     if (initializer) {
-      constValue = evaluate(initializer, seen);
+      constValue = computeConstantValue(initializer, seen);
       if (constValue !== undefined) {
         seen.set(name, constValue);
         if (typeof constValue === "number") {
@@ -193,14 +193,14 @@ export function translateEnumValues(
   });
 }
 
-// Based on the TypeScript repository's `evalConstant` in `checker.ts`.
-function evaluate(
+// Based on the TypeScript repository's `computeConstantValue` in `checker.ts`.
+function computeConstantValue(
   expr: t.Node,
   seen: PreviousEnumMembers,
 ): number | string | typeof undefined {
-  return evalConstant(expr);
+  return evaluate(expr);
 
-  function evalConstant(expr: t.Node): number | typeof undefined {
+  function evaluate(expr: t.Node): number | typeof undefined {
     switch (expr.type) {
       case "StringLiteral":
         return expr.value;
@@ -211,7 +211,7 @@ function evaluate(
       case "NumericLiteral":
         return expr.value;
       case "ParenthesizedExpression":
-        return evalConstant(expr.expression);
+        return evaluate(expr.expression);
       case "Identifier":
         return seen.get(expr.name);
       case "TemplateLiteral":
@@ -228,7 +228,7 @@ function evaluate(
     argument,
     operator,
   }: t.UnaryExpression): number | typeof undefined {
-    const value = evalConstant(argument);
+    const value = evaluate(argument);
     if (value === undefined) {
       return undefined;
     }
@@ -246,11 +246,11 @@ function evaluate(
   }
 
   function evalBinaryExpression(expr: t.BinaryExpression): number | undefined {
-    const left = evalConstant(expr.left);
+    const left = evaluate(expr.left);
     if (left === undefined) {
       return undefined;
     }
-    const right = evalConstant(expr.right);
+    const right = evaluate(expr.right);
     if (right === undefined) {
       return undefined;
     }
@@ -278,6 +278,8 @@ function evaluate(
         return left - right;
       case "%":
         return left % right;
+      case "**":
+        return left ** right;
       default:
         return undefined;
     }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/enum/constant-folding/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/enum/constant-folding/input.ts
@@ -1,10 +1,20 @@
 enum E {
     a,
-    b = 2 + 3,
-    c = 2 - 3,
-    d = 2 * 3,
-    e = 2 / 3,
-    f = -1,
-    g = 1 + 2 - 3 * 4 / -5,
-    h,
+    b = 1 | 2,
+    c = 1 & 3,
+    d = 4 >> 1,
+    e = 8 >>> 1,
+    f = 1 << 3,
+    g = 2 ^ 7,
+    h = 2 * 3,
+    i = 2 / 3,
+    j = 2 + 5,
+    k = 2 - 4,
+    l = 2.5 % 2,
+    m = 2 ** 33,
+    n = +9,
+    o = -1,
+    p = ~2,
+    q = 1 + 2 - 3 * 4 / -5,
+    r,
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/enum/constant-folding/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/enum/constant-folding/output.js
@@ -1,11 +1,21 @@
 var E;
 (function (E) {
   E[E["a"] = 0] = "a";
-  E[E["b"] = 5] = "b";
-  E[E["c"] = -1] = "c";
-  E[E["d"] = 6] = "d";
-  E[E["e"] = 0.6666666666666666] = "e";
-  E[E["f"] = -1] = "f";
-  E[E["g"] = 5.4] = "g";
-  E[E["h"] = 6.4] = "h";
+  E[E["b"] = 3] = "b";
+  E[E["c"] = 1] = "c";
+  E[E["d"] = 2] = "d";
+  E[E["e"] = 4] = "e";
+  E[E["f"] = 8] = "f";
+  E[E["g"] = 5] = "g";
+  E[E["h"] = 6] = "h";
+  E[E["i"] = 0.6666666666666666] = "i";
+  E[E["j"] = 7] = "j";
+  E[E["k"] = -2] = "k";
+  E[E["l"] = 0.5] = "l";
+  E[E["m"] = 8589934592] = "m";
+  E[E["n"] = 9] = "n";
+  E[E["o"] = -1] = "o";
+  E[E["p"] = -3] = "p";
+  E[E["q"] = 5.4] = "q";
+  E[E["r"] = 6.4] = "r";
 })(E || (E = {}));
