diff --git a/packages/babel-generator/src/generators/typescript.js b/packages/babel-generator/src/generators/typescript.js
index ea3e221843..dbdb5bce7f 100644
--- a/packages/babel-generator/src/generators/typescript.js
+++ b/packages/babel-generator/src/generators/typescript.js
@@ -317,7 +317,7 @@ export function TSParenthesizedType(node) {
 }
 
 export function TSTypeOperator(node) {
-  this.token(node.operator);
+  this.word(node.operator);
   this.space();
   this.print(node.typeAnnotation, node);
 }
diff --git a/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/input.js b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/input.js
new file mode 100644
index 0000000000..ca0cbc0136
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/input.js
@@ -0,0 +1,5 @@
+let map1: { [P in string]: number };
+let map2: { readonly [P in string]?: number };
+let map3: { +readonly [P in string]+?: number };
+let map4: { -readonly [P in string]-?: number };
+let map5: { [P in keyof Q]: number };
diff --git a/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/options.json b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/options.json
new file mode 100644
index 0000000000..cfaebcb412
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/options.json
@@ -0,0 +1,5 @@
+{
+  "compact": true,
+  "sourceType": "module",
+  "plugins": ["typescript"]
+}
diff --git a/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/output.js b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/output.js
new file mode 100644
index 0000000000..71a022d1c5
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/typescript/types-mapped-compact/output.js
@@ -0,0 +1 @@
+let map1:{[P in string]:number};let map2:{readonly[P in string]?:number};let map3:{+readonly[P in string]+?:number};let map4:{-readonly[P in string]-?:number};let map5:{[P in keyof Q]:number};
\ No newline at end of file
diff --git a/packages/babel-generator/test/fixtures/typescript/types-mapped/input.js b/packages/babel-generator/test/fixtures/typescript/types-mapped/input.js
index 6415810f05..ca0cbc0136 100644
--- a/packages/babel-generator/test/fixtures/typescript/types-mapped/input.js
+++ b/packages/babel-generator/test/fixtures/typescript/types-mapped/input.js
@@ -2,3 +2,4 @@ let map1: { [P in string]: number };
 let map2: { readonly [P in string]?: number };
 let map3: { +readonly [P in string]+?: number };
 let map4: { -readonly [P in string]-?: number };
+let map5: { [P in keyof Q]: number };
diff --git a/packages/babel-generator/test/fixtures/typescript/types-mapped/output.js b/packages/babel-generator/test/fixtures/typescript/types-mapped/output.js
index 208e77ca40..31b6e60433 100644
--- a/packages/babel-generator/test/fixtures/typescript/types-mapped/output.js
+++ b/packages/babel-generator/test/fixtures/typescript/types-mapped/output.js
@@ -1,4 +1,5 @@
 let map1: { [P in string]: number };
 let map2: { readonly [P in string]?: number };
 let map3: { +readonly [P in string]+?: number };
-let map4: { -readonly [P in string]-?: number };
\ No newline at end of file
+let map4: { -readonly [P in string]-?: number };
+let map5: { [P in keyof Q]: number };
\ No newline at end of file