Add support for callables, fixes #128

src/transform.js

@@ -622,6 +622,25 @@ const transform = {
       }
     },
   },
+  ObjectTypeCallProperty: {
+    exit(path, state) {
+      // NOTE: `value` has already been converted to a TSFunctionType
+      const { value, leadingComments, trailingComments, loc } = path.node;
+      const { typeParameters, parameters, typeAnnotation } = value;
+      const replacement = t.tsCallSignatureDeclaration(
+        typeParameters,
+        parameters,
+        typeAnnotation
+      );
+      replacement.leadingComments = leadingComments;
+      replacement.trailingComments = trailingComments;
+      replacement.loc = loc;
+
+      trackComments(replacement, state);
+
+      path.replaceWith(replacement);
+    },
+  },
   ObjectTypeProperty: {
     exit(path, state) {
       const {
@@ -751,7 +770,7 @@ const transform = {
       }
     },
     exit(path) {
-      const { exact, properties, indexers } = path.node; // TODO: callProperties, inexact
+      const { exact, callProperties, properties, indexers } = path.node; // TODO: inexact
 
       if (exact) {
         console.warn("downgrading exact object type");
@@ -762,6 +781,12 @@ const transform = {
       const elements = [];
       const spreads = [];
 
+      if (callProperties) {
+        for (const prop of callProperties) {
+          elements.push(prop);
+        }
+      }
+
       for (const prop of properties) {
         if (t.isObjectTypeSpreadProperty(prop)) {
           const { argument } = prop;

test/fixtures/convert/object-types/callables01/flow.js

@@ -0,0 +1,5 @@
+type Callable<T> = {
+  <T>(): void,
+  (string): number,
+  foo: boolean,
+};

test/fixtures/convert/object-types/callables01/ts.js

@@ -0,0 +1,5 @@
+type Callable<T> = {
+  <T>(): void;
+  (arg0: string): number;
+  foo: boolean;
+};