Make the typescript preset require a filename unless the user configured it for general use.

packages/babel-plugin-syntax-flow/src/index.js

@@ -9,6 +9,16 @@ export default declare((api, options) => {
 
   return {
     manipulateOptions(opts, parserOpts) {
+      // If the file has already enabled TS, assume that this is not a
+      // valid Flowtype file.
+      if (
+        parserOpts.plugins.some(
+          p => (Array.isArray(p) ? p[0] : p) === "typescript",
+        )
+      ) {
+        return;
+      }
+
       parserOpts.plugins.push(["flow", { all }]);
     },
   };

packages/babel-plugin-syntax-jsx/src/index.js

@@ -5,6 +5,16 @@ export default declare(api => {
 
   return {
     manipulateOptions(opts, parserOpts) {
+      // If the Typescript plugin already ran, it will have decided whether
+      // or not this is a TSX file.
+      if (
+        parserOpts.plugins.some(
+          p => (Array.isArray(p) ? p[0] : p) === "typescript",
+        )
+      ) {
+        return;
+      }
+
       parserOpts.plugins.push("jsx");
     },
   };

packages/babel-plugin-syntax-typescript/src/index.js

@@ -1,15 +1,43 @@
 import { declare } from "@babel/helper-plugin-utils";
 
-export default declare(api => {
+function removePlugin(plugins, name) {
+  const indices = [];
+  plugins.forEach((plugin, i) => {
+    const n = Array.isArray(plugin) ? plugin[0] : plugin;
+
+    if (n === name) {
+      indices.unshift(i);
+    }
+  });
+
+  for (const i of indices) {
+    plugins.splice(i, 1);
+  }
+}
+
+export default declare((api, { isTSX }) => {
   api.assertVersion(7);
 
   return {
     manipulateOptions(opts, parserOpts) {
+      const { plugins } = parserOpts;
+      // If the Flow syntax plugin already ran, remove it since Typescript
+      // takes priority.
+      removePlugin(plugins, "flow");
+
+      // If the JSX syntax plugin already ran, remomove it because JSX handling
+      // in TS depends on the extensions, and is purely dependent on 'isTSX'.
+      removePlugin(plugins, "jsx");
+
       parserOpts.plugins.push(
         "typescript",
         "objectRestSpread",
         "classProperties",
       );
+
+      if (isTSX) {
+        parserOpts.plugins.push("jsx");
+      }
     },
   };
 });

packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-preact-no/options.json

@@ -1,3 +1,3 @@
 {
-    "plugins": ["syntax-jsx", ["transform-typescript", { "jsxPragma": "h" }]]
+    "plugins": [["transform-typescript", { "jsxPragma": "h", "isTSX": true }]]
 }

packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-react-no-2/options.json

@@ -1,3 +1,3 @@
 {
-    "plugins": ["syntax-jsx", "transform-typescript"]
+    "plugins": [["transform-typescript", { "isTSX": true }]]
 }

packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-react-no/options.json

@@ -1,3 +1,3 @@
 {
-    "plugins": ["syntax-jsx", "transform-typescript"]
+    "plugins": [["transform-typescript", { "isTSX": true }]]
 }

packages/babel-preset-react/package.json

@@ -9,7 +9,6 @@
   "main": "lib/index.js",
   "dependencies": {
     "@babel/helper-plugin-utils": "7.0.0-beta.47",
-    "@babel/plugin-syntax-jsx": "7.0.0-beta.47",
     "@babel/plugin-transform-react-display-name": "7.0.0-beta.47",
     "@babel/plugin-transform-react-jsx": "7.0.0-beta.47",
     "@babel/plugin-transform-react-jsx-self": "7.0.0-beta.47",

packages/babel-preset-react/src/index.js

@@ -1,6 +1,5 @@
 import { declare } from "@babel/helper-plugin-utils";
 import transformReactJSX from "@babel/plugin-transform-react-jsx";
-import transformSyntaxJSX from "@babel/plugin-syntax-jsx";
 import transformReactDisplayName from "@babel/plugin-transform-react-display-name";
 import transformReactJSXSource from "@babel/plugin-transform-react-jsx-source";
 import transformReactJSXSelf from "@babel/plugin-transform-react-jsx-self";
@@ -27,7 +26,6 @@ export default declare((api, opts) => {
         transformReactJSX,
         { pragma, pragmaFrag, throwIfNamespace, useBuiltIns },
       ],
-      transformSyntaxJSX,
       transformReactDisplayName,
 
       development && transformReactJSXSource,

packages/babel-preset-typescript/src/index.js

@@ -1,10 +1,42 @@
 import { declare } from "@babel/helper-plugin-utils";
 import transformTypeScript from "@babel/plugin-transform-typescript";
 
-export default declare((api, { jsxPragma }) => {
-  api.assertVersion(7);
+export default declare(
+  (api, { jsxPragma, allExtensions = false, isTSX = false }) => {
+    api.assertVersion(7);
 
-  return {
-    plugins: [[transformTypeScript, { jsxPragma }]],
-  };
-});
+    if (typeof allExtensions !== "boolean") {
+      throw new Error(".allExtensions must be a boolean, or undefined");
+    }
+    if (typeof isTSX !== "boolean") {
+      throw new Error(".allExtensions must be a boolean, or undefined");
+    }
+
+    if (isTSX && !allExtensions) {
+      throw new Error("isTSX:true requires allExtensions:true");
+    }
+
+    return {
+      overrides: allExtensions
+        ? [
+            {
+              plugins: [[transformTypeScript, { jsxPragma, isTSX }]],
+            },
+          ]
+        : [
+            {
+              // Only set 'test' if explicitly requested, since it requires that
+              // Babel is being called`
+              test: /\.ts$/,
+              plugins: [[transformTypeScript, { jsxPragma }]],
+            },
+            {
+              // Only set 'test' if explicitly requested, since it requires that
+              // Babel is being called`
+              test: /\.tsx$/,
+              plugins: [[transformTypeScript, { jsxPragma, isTSX: true }]],
+            },
+          ],
+    };
+  },
+);

packages/babel-standalone/test/babel.js

@@ -23,7 +23,7 @@
     });
     it("handles the typescript preset", () => {
       const output = Babel.transform("var a: string;", {
-        presets: ["typescript"],
+        presets: [["typescript", { allExtensions: true }]],
       }).code;
       expect(output).toBe("var a;");
     });