babel · nicolo-ribaudo · Jul 21, 2023 · Jul 20, 2023 · Jul 20, 2023 · Jul 20, 2023
diff --git a/packages/babel-plugin-transform-typescript/src/enum.ts b/packages/babel-plugin-transform-typescript/src/enum.ts
@@ -173,11 +173,20 @@ export function translateEnumValues(path: NodePath<t.TSEnumDeclaration>, t: t) {
         constValue = computeConstantValue(initializerPath, seen);
         if (constValue !== undefined) {
           seen.set(name, constValue);
-          if (typeof constValue === "number") {
-            value = t.numericLiteral(constValue);
+          assert(
+            typeof constValue === "number" || typeof constValue === "string",
+          );
+          // We do not use `t.valueToNode` because `Infinity`/`NaN` might refer
+          // to a local variable. Even 1/0
+          // Revisit once https://github.com/microsoft/TypeScript/issues/55091
+          // is fixed. Note: we will have to distinguish between actual
+          // infinities and reference  to non-infinite variables names Infinity.
+          if (constValue === Infinity || Number.isNaN(constValue)) {
+            value = t.identifier(String(constValue));
+          } else if (constValue === -Infinity) {
+            value = t.unaryExpression("-", t.identifier("Infinity"));
           } else {
-            assert(typeof constValue === "string");
-            value = t.stringLiteral(constValue);
+            value = t.valueToNode(constValue);
           }
         } else {
           isPure &&= initializerPath.isPure();

diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/regression/15768/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/regression/15768/input.ts
@@ -1,11 +1,21 @@
 const v = 42;
 const v2 = Infinity;
-var Infinity = 1; // Known inconsistencies
-enum StateEnum {
-	okay = 0,
-	neg = -Infinity,
-	pos = Infinity,
-	nan = NaN,
-	ext = v,
-  ext2 = v2,
+const v3 = NaN;
+
+{
+	let Infinity = 1;
+	let NaN = 2;
+
+	enum StateEnum {
+		okay = 0,
+		neg = -Infinity,
+		pos = Infinity,
+		nan = NaN,
+		negReal = -1 / 0,
+		posReal = 1 / 0,
+		nanReal = 0 / 0,
+		ext = v,
+		ext2 = v2,
+		ext3 = v3,
+	}
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/regression/15768/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/regression/15768/output.js
@@ -1,12 +1,20 @@
 const v = 42;
 const v2 = Infinity;
-var Infinity = 1; // Known inconsistencies
-var StateEnum = /*#__PURE__*/function (StateEnum) {
-  StateEnum[StateEnum["okay"] = 0] = "okay";
-  StateEnum[StateEnum["neg"] = -Infinity] = "neg";
-  StateEnum[StateEnum["pos"] = Infinity] = "pos";
-  StateEnum[StateEnum["nan"] = NaN] = "nan";
-  StateEnum[StateEnum["ext"] = 42] = "ext";
-  StateEnum[StateEnum["ext2"] = 1] = "ext2";
-  return StateEnum;
-}(StateEnum || {});
+const v3 = NaN;
+{
+  let Infinity = 1;
+  let NaN = 2;
+  let StateEnum = /*#__PURE__*/function (StateEnum) {
+    StateEnum[StateEnum["okay"] = 0] = "okay";
+    StateEnum[StateEnum["neg"] = -Infinity] = "neg";
+    StateEnum[StateEnum["pos"] = Infinity] = "pos";
+    StateEnum[StateEnum["nan"] = NaN] = "nan";
+    StateEnum[StateEnum["negReal"] = -Infinity] = "negReal";
+    StateEnum[StateEnum["posReal"] = Infinity] = "posReal";
+    StateEnum[StateEnum["nanReal"] = NaN] = "nanReal";
+    StateEnum[StateEnum["ext"] = 42] = "ext";
+    StateEnum[StateEnum["ext2"] = Infinity] = "ext2";
+    StateEnum[StateEnum["ext3"] = NaN] = "ext3";
+    return StateEnum;
+  }({});
+}
diff --git a/packages/babel-types/scripts/generators/docs.js b/packages/babel-types/scripts/generators/docs.js
@@ -45,6 +45,9 @@ const customTypes = {
   ClassPrivateProperty: {
     computed: "'false'",
   },
+  NumericLiteral: {
+    value: "a non-negative finite `number`",
+  },
 };
 const APIHistory = {
   ClassProperty: [["v7.6.0", "Supports `static`"]],

diff --git a/packages/babel-types/src/definitions/core.ts b/packages/babel-types/src/definitions/core.ts
@@ -611,7 +611,33 @@ defineType("NumericLiteral", {
   deprecatedAlias: "NumberLiteral",
   fields: {
     value: {
-      validate: assertValueType("number"),
+      validate: chain(
+        assertValueType("number"),
+        Object.assign(
+          function (node, key, val) {
+            if (1 / val < 0 || !Number.isFinite(val)) {
+              const error = new Error(
+                "NumericLiterals must be non-negative finite numbers. " +
+                  `You can use t.valueToNode(${val}) instead.`,
+              );
+              if (process.env.BABEL_8_BREAKING) {
+                // TODO(@nicolo-ribaudo) Fix regenerator to not pass negative
+                // numbers here.
+                if (!IS_STANDALONE) {
+                  if (!new Error().stack.includes("regenerator")) {
+                    throw error;
+                  }
+                }
+              } else {
+                // TODO: Enable this warning once regenerator is fixed.
+                // https://github.com/facebook/regenerator/pull/680
+                // console.warn(error);
+              }
+            }
+          } satisfies Validator,
+          { type: "number" },
+        ),
+      ),
     },
   },
   aliases: ["Expression", "Pureish", "Literal", "Immutable"],

diff --git a/packages/babel-types/test/builders/core.js b/packages/babel-types/test/builders/core.js
@@ -0,0 +1,13 @@
+import * as t from "../../lib/index.js";
+
+const itBabel8 = process.env.BABEL_8_BREAKING ? it : it.skip;
+
+describe("builders", function () {
+  itBabel8("t.numericLiteral expexts a non-negative finite value", () => {
+    expect(() => t.numericLiteral(-1)).toThrow();
+    expect(() => t.numericLiteral(-0)).toThrow();
+    expect(() => t.numericLiteral(-Infinity)).toThrow();
+    expect(() => t.numericLiteral(Infinity)).toThrow();
+    expect(() => t.numericLiteral(NaN)).toThrow();
+  });
+});