Improve if/else printing and other clauses

src/printer.js

@@ -860,13 +860,6 @@ function genericPrintNoParens(path, options, print) {
       ") ",
       path.call(print, "body")
     ]);
-  // var con = adjustClause(path.call(print, "consequent"), options),
-  //     parts = ["if (", path.call(print, "test"), ")", con];
-  // if (n.alternate)
-  //     parts.push(
-  //         endsWithBrace(con) ? " else" : "\nelse",
-  //         adjustClause(path.call(print, "alternate"), options));
-  // return concat(parts);
   case "IfStatement":
     const con = adjustClause(path.call(print, "consequent"), options);
 
@@ -884,15 +877,25 @@ function genericPrintNoParens(path, options, print) {
     ];
 
     if (n.alternate) {
-      const hasBraces = getFirstString(con) === "{";
+      const hasBraces = isCurlyBracket(con);
+      const isEmpty = isEmptyBlock(con);
 
-      parts.push((hasBraces ? " else" : "\nelse"), adjustClause(
+      if (hasBraces && !isEmpty) {
-        path.call(print, "alternate"),
+        parts.push(" else");
-        options
+      } else {
-      ));
+        parts.push(concat([hardline, "else"]));
+      }
+
+      parts.push(
+        adjustClause(
+          path.call(print, "alternate"),
+          options,
+          n.alternate.type === "IfStatement"
+        )
+      );
     }
 
-    return concat(parts);
+    return group(concat(parts));
   case "ForStatement":
     // TODO Get the for (;;) case right.
     return concat([
@@ -952,7 +955,7 @@ function genericPrintNoParens(path, options, print) {
     var clause = adjustClause(path.call(print, "body"), options);
     var doBody = concat([ "do", clause ]);
     var parts = [ doBody ];
-    const hasBraces = getFirstString(clause) === "{";
+    const hasBraces = isCurlyBracket(clause);
 
     if (hasBraces)
       parts.push(" while");
@@ -1898,14 +1901,24 @@ function printClass(path, print) {
   return parts;
 }
 
-function adjustClause(clause, options) {
+function adjustClause(clause, options, forceSpace) {
-  if (getFirstString(clause) === "{") {
+  if (isCurlyBracket(clause) || forceSpace) {
     return concat([ " ", clause ]);
   }
 
   return indent(options.tabWidth, concat([ hardline, clause ]));
 }
 
+function isCurlyBracket(doc) {
+  const str = getFirstString(doc);
+  return str === "{" || str === "{}";
+}
+
+function isEmptyBlock(doc) {
+  const str = getFirstString(doc);
+  return str === "{}";
+}
+
 function lastNonSpaceCharacter(lines) {
   var pos = lines.lastPos();
   do {

tests/binary/__snapshots__/jsfmt.spec.js.snap

@@ -118,14 +118,11 @@ let tests = [
     false in [];
   },
   function() {
-    if (\"foo\" in 123)
+    if (\"foo\" in 123) {}
-      {}
 
-    if (!\"foo\" in {})
+    if (!\"foo\" in {}) {}
-      {}
 
-    if (!(\"foo\" in {}))
+    if (!(\"foo\" in {})) {}
-      {}
   },
   function(x: Object, y: mixed) {
     \"foo\" in x;

tests/binding/__snapshots__/jsfmt.spec.js.snap

@@ -705,43 +705,37 @@ function try_scope() {
 function for_scope_let() {
   let a: number = 0;
 
-  for (let a = \"\"; ; )
+  for (let a = \"\"; ; ) {}
-    {}
 }
 
 function for_scope_var() {
   var a: number = 0;
 
-  for (var a = \"\"; ; )
+  for (var a = \"\"; ; ) {}
-    {}
 }
 
 function for_in_scope_let(o: Object) {
   let a: number = 0;
 
-  for (let a in o)
+  for (let a in o) {}
-    {}
 }
 
 function for_in_scope_var(o: Object) {
   var a: number = 0;
 
-  for (var a in o)
+  for (var a in o) {}
-    {}
 }
 
 function for_of_scope_let(xs: string[]) {
   let a: number = 0;
 
-  for (let a of xs)
+  for (let a of xs) {}
-    {}
 }
 
 function for_of_scope_var(xs: string[]) {
   var a: number = 0;
 
-  for (var a of xs)
+  for (var a of xs) {}
-    {}
 }
 
 function default_param_1() {

tests/bom/__snapshots__/jsfmt.spec.js.snap

@@ -192,32 +192,23 @@ a.delete(\"xx\");
 
 a.delete(3);
 
-for (let x: string of a.keys())
+for (let x: string of a.keys()) {}
-  {}
 
-for (let x: number of a.keys())
+for (let x: number of a.keys()) {}
-  {}
 
-for (let x: string | File of a.values())
+for (let x: string | File of a.values()) {}
-  {}
 
-for (let x: string | File | Blob of a.values())
+for (let x: string | File | Blob of a.values()) {}
-  {}
 
-for (let [ x, y ]: [string, string | File] of a.entries())
+for (let [ x, y ]: [string, string | File] of a.entries()) {}
-  {}
 
-for (let [ x, y ]: [string, string | File | Blob] of a.entries())
+for (let [ x, y ]: [string, string | File | Blob] of a.entries()) {}
-  {}
 
-for (let [ x, y ]: [number, string] of a.entries())
+for (let [ x, y ]: [number, string] of a.entries()) {}
-  {}
 
-for (let [ x, y ]: [string, number] of a.entries())
+for (let [ x, y ]: [string, number] of a.entries()) {}
-  {}
 
-for (let [ x, y ]: [number, number] of a.entries())
+for (let [ x, y ]: [number, number] of a.entries()) {}
-  {}
 "
 `;
 

tests/closure/__snapshots__/jsfmt.spec.js.snap

@@ -313,17 +313,15 @@ function h(x: number | string | boolean) {
     call_me = () => {
       var y: number = const_x;
     };
-  } else
+  } else if (typeof const_x == \"string\") {
-    if (typeof const_x == \"string\") {
+    call_me = () => {
-      call_me = () => {
+      var y: string = const_x;
-        var y: string = const_x;
+    };
-      };
+  } else if (typeof const_x == \"boolean\") {
-    } else
+    call_me = () => {
-      if (typeof const_x == \"boolean\") {
+      var y: boolean = const_x;
-        call_me = () => {
+    };
-          var y: boolean = const_x;
+  }
-        };
-      }
 
   var var_x = x;
 
@@ -331,17 +329,15 @@ function h(x: number | string | boolean) {
     call_me = () => {
       var y: number = var_x;
     };
-  } else
+  } else if (typeof var_x == \"string\") {
-    if (typeof var_x == \"string\") {
+    call_me = () => {
-      call_me = () => {
+      var y: string = var_x;
-        var y: string = var_x;
+    };
-      };
+  } else if (typeof var_x == \"boolean\") {
-    } else
+    call_me = () => {
-      if (typeof var_x == \"boolean\") {
+      var y: boolean = var_x;
-        call_me = () => {
+    };
-          var y: boolean = var_x;
+  }
-        };
-      }
 }
 
 call_me();

tests/error_messages/__snapshots__/jsfmt.spec.js.snap

@@ -1,7 +1,6 @@
 exports[`test errors.js 1`] = `
 "if (typeof define === \'function\' && define.amd) { }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-if (typeof define === \"function\" && define.amd)
+if (typeof define === \"function\" && define.amd) {}
-  {}
 "
 `;

tests/generators/__snapshots__/jsfmt.spec.js.snap

@@ -180,14 +180,11 @@ class GeneratorExamples {
   *widen_next() {
     var x = yield 0;
 
-    if (typeof x === \"number\")
+    if (typeof x === \"number\") {}
-      {}
+    else if (typeof x === \"boolean\") {}
-else
+    else {
-      if (typeof x === \"boolean\")
+      (x: string);
-        {}
+    }
-else {
-        (x: string);
-      }
   }
   *widen_yield() {
     yield 0;
@@ -244,14 +241,11 @@ for (var x of examples.infer_stmt()) {
 
 var infer_stmt_next = examples.infer_stmt().next(0).value;
 
-if (typeof infer_stmt_next === \"undefined\")
+if (typeof infer_stmt_next === \"undefined\") {}
-  {}
+else if (typeof infer_stmt_next === \"number\") {}
-else
-  if (typeof infer_stmt_next === \"number\")
-    {}
 else {
-    (infer_stmt_next: boolean);
+  (infer_stmt_next: boolean);
-  }
+}
 
 examples.widen_next().next(0);
 
@@ -260,14 +254,11 @@ examples.widen_next().next(\"\");
 examples.widen_next().next(true);
 
 for (var x of examples.widen_yield()) {
-  if (typeof x === \"number\")
+  if (typeof x === \"number\") {}
-    {}
+  else if (typeof x === \"boolean\") {}
-else
+  else {
-    if (typeof x === \"boolean\")
+    (x: string);
-      {}
+  }
-else {
-      (x: string);
-    }
 }
 
 examples.delegate_next_generator().next(\"\");
@@ -325,14 +316,11 @@ for (var x of examples.infer_stmt()) {
 
 var infer_stmt_next = examples.infer_stmt().next(0).value;
 
-if (typeof infer_stmt_next === \"undefined\")
+if (typeof infer_stmt_next === \"undefined\") {}
-  {}
+else if (typeof infer_stmt_next === \"number\") {}
-else
-  if (typeof infer_stmt_next === \"number\")
-    {}
 else {
-    (infer_stmt_next: boolean);
+  (infer_stmt_next: boolean);
-  }
+}
 "
 `;
 
@@ -525,26 +513,20 @@ for (var x of infer_stmt()) {
 
 var infer_stmt_next = infer_stmt().next(0).value;
 
-if (typeof infer_stmt_next === \"undefined\")
+if (typeof infer_stmt_next === \"undefined\") {}
-  {}
+else if (typeof infer_stmt_next === \"number\") {}
-else
-  if (typeof infer_stmt_next === \"number\")
-    {}
 else {
-    (infer_stmt_next: boolean);
+  (infer_stmt_next: boolean);
-  }
+}
 
 function* widen_next() {
   var x = yield 0;
 
-  if (typeof x === \"number\")
+  if (typeof x === \"number\") {}
-    {}
+  else if (typeof x === \"boolean\") {}
-else
+  else {
-    if (typeof x === \"boolean\")
+    (x: string);
-      {}
+  }
-else {
-      (x: string);
-    }
 }
 
 widen_next().next(0);
@@ -562,14 +544,11 @@ function* widen_yield() {
 }
 
 for (var x of widen_yield()) {
-  if (typeof x === \"number\")
+  if (typeof x === \"number\") {}
-    {}
+  else if (typeof x === \"boolean\") {}
-else
+  else {
-    if (typeof x === \"boolean\")
+    (x: string);
-      {}
+  }
-else {
-      (x: string);
-    }
 }
 
 function* delegate_next_generator() {

tests/instanceof/__snapshots__/jsfmt.spec.js.snap

@@ -113,7 +113,7 @@ function consumer1(b) {
 
   if (g instanceof X2)
     g.foo = \"1337\";
-else
+  else
     g.foo = 1337;
 }
 
@@ -140,7 +140,7 @@ function consumer3(b) {
 
   if (g.bar instanceof X2)
     g.bar.foo = \"1337\";
-else
+  else
     g.bar.foo = 1337;
 }
 
@@ -167,7 +167,7 @@ function consumer5(b) {
 
   if (g.baz.bar instanceof X2)
     g.baz.bar.foo = \"1337\";
-else
+  else
     g.baz.bar.foo = 1337;
 }
 
@@ -182,7 +182,7 @@ class C {
   m() {
     if (this instanceof D)
       alert(this.s);
-else
+    else
       alert(\"nope\");
   }
 }

tests/iter/__snapshots__/jsfmt.spec.js.snap

@@ -81,7 +81,6 @@ for (var x in null) {
   foo(x);
 }
 
-for (var y in this)
+for (var y in this) {}
-  {}
 "
 `;

tests/lib/__snapshots__/jsfmt.spec.js.snap

@@ -21,7 +21,6 @@ a.delete(\"foobar\");
 
 var b = undefined;
 
-if (undefined)
+if (undefined) {}
-  {}
 "
 `;

tests/more_path/__snapshots__/jsfmt.spec.js.snap

@@ -111,8 +111,7 @@ function goofy() {
 
   if (typeof x == \"function\") {
     x();
-  } else
+  } else {}
-    {}
 }
 
 function goofy2() {
@@ -126,8 +125,7 @@ function goofy2() {
 
   if (typeof y == \"function\") {
     y();
-  } else
+  } else {}
-    {}
 }
 
 module.exports = true;
@@ -252,8 +250,7 @@ class D {
 }
 
 function baz(x: D) {
-  if (x instanceof A)
+  if (x instanceof A) {}
-    {}
 }
 
 module.exports = \"sigma\";

tests/predicates-declared/__snapshots__/jsfmt.spec.js.snap

@@ -67,15 +67,13 @@ if (m.bind(o)) {
 class D {
   m: Function;
   n() {
-    if (this.m({}))
+    if (this.m({})) {}
-      {}
   }
 }
 declare var m: Function;
 const x = \"\";
 
-if (m.bind(this)(x))
+if (m.bind(this)(x)) {}
-  {}
 "
 `;
 
@@ -246,8 +244,7 @@ function f(_this: { m: ?Meeting }): string {
     return \"0\";
   }
 
-  if (_this.m.es.some(a => a.fbid === 0))
+  if (_this.m.es.some(a => a.fbid === 0)) {}
-    {}
 
   return \"3\";
 }

tests/refi/__snapshots__/jsfmt.spec.js.snap

@@ -95,9 +95,8 @@ var tests = [
     }
   },
   function() {
-    if (x == null)
+    if (x == null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
@@ -108,22 +107,19 @@ else {
     var y: string = x;
   },
   function() {
-    if (!(x != null))
+    if (!(x != null)) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
-    if (x != null)
+    if (x != null) {}
-      {}
 
     var y: string = x;
   },
   function() {
-    if (x != null)
+    if (x != null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
@@ -425,9 +421,8 @@ var tests = [
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p == null)
+    if (x.p == null) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
@@ -442,9 +437,8 @@ else {
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (!(x.p != null))
+    if (!(x.p != null)) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
@@ -469,17 +463,15 @@ else {
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p != null)
+    if (x.p != null) {}
-      {}
 
     var y: string = x.p;
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p != null)
+    if (x.p != null) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
@@ -512,9 +504,8 @@ else {
   function() {
     var x: { y: ?string } = { y: null };
 
-    if (x.y)
+    if (x.y) {}
-      {}
+    else {
-else {
       x.y = \"foo\";
     }
 
@@ -554,10 +545,9 @@ else {
 
     if (typeof x.y == \"number\") {
       x.y = \"foo\";
-    } else
+    } else if (typeof x.y == \"boolean\") {
-      if (typeof x.y == \"boolean\") {
+      x.y = \"bar\";
-        x.y = \"bar\";
+    }
-      }
 
     (x.y: boolean);
   },
@@ -613,14 +603,12 @@ else {
     (x.y: string);
   },
   function(x: string) {
-    if (x === \"a\")
+    if (x === \"a\") {}
-      {}
 
     (x: \"b\");
   },
   function(x: mixed) {
-    if (typeof x.bar === \"string\")
+    if (typeof x.bar === \"string\") {}
-      {}
 
     (x: string & number);
   },
@@ -628,8 +616,7 @@ else {
     let x: { foo: ?string } = { foo: null };
 
     if (!x.foo) {
-      if (false)
+      if (false) {}
-        {}
 
       x.foo = \"foo\";
     }
@@ -640,8 +627,7 @@ else {
     let x: { foo: ?string } = { foo: null };
 
     if (!x.foo) {
-      while (false)
+      while (false) {}
-        {}
 
       x.foo = \"foo\";
     }
@@ -652,8 +638,7 @@ else {
     let x: { foo: ?string } = { foo: null };
 
     if (!x.foo) {
-      for (var i = 0; i < 0; i++)
+      for (var i = 0; i < 0; i++) {}
-        {}
 
       x.foo = \"foo\";
     }
@@ -882,9 +867,8 @@ var paths = [
   function() {
     var x: ?string = \"xxx\";
 
-    if (x == null)
+    if (x == null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
@@ -899,9 +883,8 @@ else {
   function() {
     var x: ?string = \"xxx\";
 
-    if (!(x != null))
+    if (!(x != null)) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
@@ -917,17 +900,15 @@ else {
   function() {
     var x: ?string = \"xxx\";
 
-    if (x != null)
+    if (x != null) {}
-      {}
 
     var y: string = x;
   },
   function() {
     var x: ?string = \"xxx\";
 
-    if (x != null)
+    if (x != null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
@@ -1169,27 +1150,24 @@ var null_tests = [
   function() {
     var x: ?string = \"xxx\";
 
-    if (x == null)
+    if (x == null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p == null)
+    if (x.p == null) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (x.p.q == null)
+    if (x.p.q == null) {}
-      {}
+    else {
-else {
       var y: string = x.p.q;
     }
   },
@@ -1217,27 +1195,24 @@ else {
   function() {
     var x: ?string = \"xxx\";
 
-    if (x === null)
+    if (x === null) {}
-      {}
+    else {
-else {
       var y: string | void = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p === null)
+    if (x.p === null) {}
-      {}
+    else {
-else {
       var y: string | void = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (x.p.q === null)
+    if (x.p.q === null) {}
-      {}
+    else {
-else {
       var y: string | void = x.p.q;
     }
   }
@@ -1247,7 +1222,7 @@ class C {
   ensure0(): string {
     if (this.p != null)
       return this.p;
-else
+    else
       return \"\";
   }
   ensure1(): string {
@@ -1259,7 +1234,7 @@ else
   ensure2(): string | void {
     if (this.p !== null)
       return this.p;
-else
+    else
       return \"\";
   }
   ensure3(): string | void {
@@ -1273,13 +1248,13 @@ class D extends C {
   ensure100(): string {
     if (super.p != null)
       return super.p;
-else
+    else
       return \"\";
   }
   ensure101(): string {
     if (super.p == null)
       return \"\";
-else
+    else
       return super.p;
   }
   ensure103(): string {
@@ -1623,27 +1598,24 @@ var null_tests = [
   function() {
     var x: ?string = \"xxx\";
 
-    if (typeof x != \"string\")
+    if (typeof x != \"string\") {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (typeof x.p != \"string\")
+    if (typeof x.p != \"string\") {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (typeof x.p.q != \"string\")
+    if (typeof x.p.q != \"string\") {}
-      {}
+    else {
-else {
       var y: string = x.p.q;
     }
   },
@@ -1671,27 +1643,24 @@ else {
   function() {
     var x: ?string = \"xxx\";
 
-    if (typeof x !== \"string\")
+    if (typeof x !== \"string\") {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (typeof x.p !== \"string\")
+    if (typeof x.p !== \"string\") {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (typeof x.p.q !== \"string\")
+    if (typeof x.p.q !== \"string\") {}
-      {}
+    else {
-else {
       var y: string = x.p.q;
     }
   }
@@ -1701,25 +1670,25 @@ class A {
   ensure0(): string {
     if (typeof this.p == \"string\")
       return this.p;
-else
+    else
       return \"\";
   }
   ensure1(): string {
     if (typeof this.p != \"string\")
       return \"\";
-else
+    else
       return this.p;
   }
   ensure2(): string | void {
     if (typeof this.p === \"string\")
       return this.p;
-else
+    else
       return \"\";
   }
   ensure3(): string | void {
     if (typeof this.p !== \"string\")
       return \"\";
-else
+    else
       return this.p;
   }
 }
@@ -1845,27 +1814,24 @@ var undef_tests = [
   function() {
     var x: ?string = \"xxx\";
 
-    if (x === undefined || x === null)
+    if (x === undefined || x === null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p === undefined || x.p === null)
+    if (x.p === undefined || x.p === null) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (x.p.q === undefined || x.p.q === null)
+    if (x.p.q === undefined || x.p.q === null) {}
-      {}
+    else {
-else {
       var y: string = x.p.q;
     }
   }
@@ -1875,13 +1841,13 @@ class A {
   ensure0(): string {
     if (this.p !== undefined && this.p !== null)
       return this.p;
-else
+    else
       return \"\";
   }
   ensure1(): string {
     if (this.p === undefined || this.p === null)
       return \"\";
-else
+    else
       return this.p;
   }
 }
@@ -2007,27 +1973,24 @@ var void_tests = [
   function() {
     var x: ?string = \"xxx\";
 
-    if (x === void 0 || x === null)
+    if (x === void 0 || x === null) {}
-      {}
+    else {
-else {
       var y: string = x;
     }
   },
   function() {
     var x: { p: ?string } = { p: \"xxx\" };
 
-    if (x.p === void 0 || x.p === null)
+    if (x.p === void 0 || x.p === null) {}
-      {}
+    else {
-else {
       var y: string = x.p;
     }
   },
   function() {
     var x: { p: { q: ?string } } = { p: { q: \"xxx\" } };
 
-    if (x.p.q === void 0 || x.p.q === null)
+    if (x.p.q === void 0 || x.p.q === null) {}
-      {}
+    else {
-else {
       var y: string = x.p.q;
     }
   }
@@ -2037,13 +2000,13 @@ class A {
   ensure0(): string {
     if (this.p !== void 0 && this.p !== null)
       return this.p;
-else
+    else
       return \"\";
   }
   ensure1(): string {
     if (this.p === void 0 || this.p === null)
       return \"\";
-else
+    else
       return this.p;
   }
 }

tests/refinements/__snapshots__/jsfmt.spec.js.snap

@@ -390,29 +390,22 @@ let tests = [
 // ok
 let tests = [
   function(x: string, y: number) {
-    if (x == y)
+    if (x == y) {}
-      {}
 
-    if (x === y)
+    if (x === y) {}
-      {}
   },
   function(x: string) {
-    if (x == undefined)
+    if (x == undefined) {}
-      {}
 
-    if (x == void 0)
+    if (x == void 0) {}
-      {}
   },
   function(x: string) {
-    if (x == null)
+    if (x == null) {}
-      {}
   },
   function(x: { y: \"foo\" } | { y: \"bar\" }) {
-    if (x.y == 123)
+    if (x.y == 123) {}
-      {}
 
-    if (x.y === 123)
+    if (x.y === 123) {}
-      {}
   }
 ];
 "
@@ -869,30 +862,23 @@ function foo5() {
 }
 
 function foo6(o: mixed) {
-  if (o.bar)
+  if (o.bar) {}
-    {}
 }
 
 function foo7(o: mixed) {
-  if (typeof o.bar === \"string\")
+  if (typeof o.bar === \"string\") {}
-    {}
 
-  if (o && typeof o.bar === \"string\")
+  if (o && typeof o.bar === \"string\") {}
-    {}
 
-  if (o != null && typeof o.bar === \"string\")
+  if (o != null && typeof o.bar === \"string\") {}
-    {}
 
-  if (o !== null && o !== undefined && typeof o.bar === \"string\")
+  if (o !== null && o !== undefined && typeof o.bar === \"string\") {}
-    {}
 }
 
 function foo8(o: { p: mixed }) {
-  if (o.p && o.p.q)
+  if (o.p && o.p.q) {}
-    {}
 
-  if (o.p && o.p.q && o.p.q.r)
+  if (o.p && o.p.q && o.p.q.r) {}
-    {}
 }
 "
 `;
@@ -1536,12 +1522,10 @@ let tests = [
     }
   },
   function(num: number, obj: { foo: number }) {
-    if (num === obj.bar)
+    if (num === obj.bar) {}
-      {}
   },
   function(num: number, obj: { [key: string]: number }) {
-    if (num === obj.bar)
+    if (num === obj.bar) {}
-      {}
   },
   function(n: number): Mode {
     if (n !== 0 && n !== 1 && n !== 2) {
@@ -1553,10 +1537,9 @@ let tests = [
   function(s: number): ?Mode {
     if (s === 0) {
       return s;
-    } else
+    } else if (s === 3) {
-      if (s === 3) {
+      return s;
-        return s;
+    }
-      }
   },
   function(mode: Mode) {
     switch (mode) {
@@ -1928,15 +1911,13 @@ function waldo() {
 
 function global_in_conditional0(x: number) {
   if (x != 0) {
-    if (BAZ)
+    if (BAZ) {}
-      {}
   }
 }
 
 function global_in_conditional2(x: number) {
   for (var i = 0; i < 100; i++) {
-    if (BAZ)
+    if (BAZ) {}
-      {}
   }
 }
 "
@@ -2166,12 +2147,10 @@ let tests = [
     }
   },
   function(str: string, obj: { foo: string }) {
-    if (str === obj.bar)
+    if (str === obj.bar) {}
-      {}
   },
   function(str: string, obj: { [key: string]: string }) {
-    if (str === obj.bar)
+    if (str === obj.bar) {}
-      {}
   },
   function(str: string): Mode {
     var ch = str[0];
@@ -2185,10 +2164,9 @@ let tests = [
   function(s: string): ?Mode {
     if (s === \"a\") {
       return s;
-    } else
+    } else if (s === \"d\") {
-      if (s === \"d\") {
+      return s;
-        return s;
+    }
-      }
   },
   function(mode: Mode) {
     switch (mode) {
@@ -2800,7 +2778,7 @@ type NonCitizen = { citizen: false, nationality: string };
 function nationality(x: Citizen | NonCitizen) {
   if (x.citizen)
     return \"Shire\";
-else
+  else
     return x.nationality;
 }
 
@@ -2811,18 +2789,14 @@ let tests = [
     }
   },
   function test8(x: { foo: { bar: 1 } }) {
-    if (x.foo.bar === 1)
+    if (x.foo.bar === 1) {}
-      {}
 
-    if (x.fooTypo.bar === 1)
+    if (x.fooTypo.bar === 1) {}
-      {}
   },
   function(x: A) {
-    if (x.kind === null.toString())
+    if (x.kind === null.toString()) {}
-      {}
 
-    if ({ kind: 1 }.kind === null.toString())
+    if ({ kind: 1 }.kind === null.toString()) {}
-      {}
   },
   function(
     x: Array<string>,
@@ -2833,8 +2807,7 @@ let tests = [
     s: Function,
     t: () => void
   ) {
-    if (x.length === 0)
+    if (x.length === 0) {}
-      {}
 
     if (x.legnth === 0) {
       (x.legnth: number);
@@ -2842,8 +2815,7 @@ let tests = [
       (x.legnth: string);
     }
 
-    if (y.length === 0)
+    if (y.length === 0) {}
-      {}
 
     if (y.legnth === 0) {
       (y.legnth: number);
@@ -2851,8 +2823,7 @@ let tests = [
       (y.legnth: string);
     }
 
-    if (z.toString === 0)
+    if (z.toString === 0) {}
-      {}
 
     if (z.toStirng === 0) {
       (z.toStirng: number);
@@ -2860,8 +2831,7 @@ let tests = [
       (z.toStirng: string);
     }
 
-    if (q.valueOf === 0)
+    if (q.valueOf === 0) {}
-      {}
 
     if (q.valeuOf === 0) {
       (q.valeuOf: number);
@@ -2873,15 +2843,13 @@ let tests = [
       (r.toStirng: empty);
     }
 
-    if (s.call === 0)
+    if (s.call === 0) {}
-      {}
 
     if (s.calll === 0) {
       (t.calll: empty);
     }
 
-    if (t.call === 0)
+    if (t.call === 0) {}
-      {}
 
     if (t.calll === 0) {
       (t.calll: empty);
@@ -3276,9 +3244,8 @@ function undef_var(x: ?number) {
 }
 
 function undef_var_rev(x: ?number) {
-  if (x === null || x === undefined)
+  if (x === null || x === undefined) {}
-    {}
+  else {
-else {
     var y = x * 1000;
   }
 }
@@ -3290,9 +3257,8 @@ function undef_prop(x: { x: ?number }) {
 }
 
 function undef_prop_rev(x: { x: ?number }) {
-  if (x.x === null || x.x === undefined)
+  if (x.x === null || x.x === undefined) {}
-    {}
+  else {
-else {
     var y = x.x * 1000;
   }
 }
@@ -3304,9 +3270,8 @@ function undef_var_fail(x: ?number) {
 }
 
 function undef_var_fail_rev(x: ?number) {
-  if (x === undefined)
+  if (x === undefined) {}
-    {}
+  else {
-else {
     var y = x * 1000;
   }
 }
@@ -3318,9 +3283,8 @@ function undef_prop_fail(x: { x: ?number }) {
 }
 
 function undef_prop_fail_rev(x: { x: ?number }) {
-  if (x.x === undefined)
+  if (x.x === undefined) {}
-    {}
+  else {
-else {
     var y = x.x * 1000;
   }
 }
@@ -3511,9 +3475,8 @@ function void_var(x: ?number) {
 }
 
 function void_var_rev(x: ?number) {
-  if (x === null || x === void 0)
+  if (x === null || x === void 0) {}
-    {}
+  else {
-else {
     var y = x * 1000;
   }
 }
@@ -3525,9 +3488,8 @@ function void_pro(x: { x: ?number }) {
 }
 
 function void_pro_rev(x: { x: ?number }) {
-  if (x.x === null || x.x === void 0)
+  if (x.x === null || x.x === void 0) {}
-    {}
+  else {
-else {
     var y = x.x * 1000;
   }
 }
@@ -3539,9 +3501,8 @@ function void_var_fail(x: ?number) {
 }
 
 function void_var_fail_rev(x: ?number) {
-  if (x === void 0)
+  if (x === void 0) {}
-    {}
+  else {
-else {
     var y = x * 1000;
   }
 }
@@ -3553,9 +3514,8 @@ function void_pro_fail(x: { x: ?number }) {
 }
 
 function void_pro_fail_rev(x: { x: ?number }) {
-  if (x.x === void 0)
+  if (x.x === void 0) {}
-    {}
+  else {
-else {
     var y = x.x * 1000;
   }
 }
@@ -3567,9 +3527,8 @@ function void_var_side_effect(x: ?number) {
 }
 
 function void_var_side_effect_rev(x: ?number) {
-  if (x === null || x === void (x * 1000))
+  if (x === null || x === void (x * 1000)) {}
-    {}
+  else {
-else {
     var y = x * 1000;
   }
 }
@@ -3581,9 +3540,8 @@ function void_prop_side_effect(x: { x: ?number }) {
 }
 
 function void_prop_side_effect_rev(x: { x: ?number }) {
-  if (x.x === null || x.x === void (x.x * 1000))
+  if (x.x === null || x.x === void (x.x * 1000)) {}
-    {}
+  else {
-else {
     var y = x.x * 1000;
   }
 }

tests/super/__snapshots__/jsfmt.spec.js.snap

@@ -238,7 +238,7 @@ class H extends A {
   constructor() {
     if (Math.random() < 0.5)
       super();
-else
+    else
       super();
 
     this.y;

tests/tagged-unions/__snapshots__/jsfmt.spec.js.snap

@@ -45,12 +45,11 @@ type Foobar = Foo | Bar;
 function foobar(x: Foobar): string {
   if (x.type === \"foo\") {
     return foo(x);
-  } else
+  } else if (x.type === \"bar\") {
-    if (x.type === \"bar\") {
+    return bar(x);
-      return bar(x);
+  } else {
-    } else {
+    return \"unknown\";
-      return \"unknown\";
+  }
-    }
 }
 
 function foo(x: Foo): string {

tests/try/__snapshots__/jsfmt.spec.js.snap

@@ -572,8 +572,7 @@ function bar(response) {
     throw new Error(\"...\");
   }
 
-  if (payload.error)
+  if (payload.error) {}
-    {}
 }
 
 function qux() {

tests/type-at-pos/__snapshots__/jsfmt.spec.js.snap

@@ -209,14 +209,11 @@ if (Array.isArray(x)) {}
 /* @flow */
 let x = 0;
 
-if (x == null)
+if (x == null) {}
-  {}
 
-if (x == undefined)
+if (x == undefined) {}
-  {}
 
-if (Array.isArray(x))
+if (Array.isArray(x)) {}
-  {}
 "
 `;
 

tests/type-destructors/__snapshots__/jsfmt.spec.js.snap

@@ -55,7 +55,7 @@ type Obj_Prop_x = $PropertyType<Obj, \"x\">;
 function foo(o: Obj): $PropertyType<Obj, \"x\"> {
   if (false)
     return o.x;
-else
+  else
     return 0;
 }
 "

tests/union_new/__snapshots__/jsfmt.spec.js.snap

@@ -314,7 +314,7 @@ type X = ({ a: true } & { b: string }) | ({ a: false } & { c: string });
 function hello(x: X): string {
   if (x.a === true)
     return x.b;
-else
+  else
     return x.c;
 }
 "
@@ -1192,7 +1192,7 @@ type Cons = { kind: \"cons\", next: List };
 function length(list: List) {
   if (list.kind === \"cons\")
     return length(list.next) + 1;
-else
+  else
     return 0;
 }
 
@@ -1548,7 +1548,7 @@ export type T = Success | Error;
 function foo(x: T) {
   if (x.type === \"SUCCESS\")
     return x.result;
-else
+  else
     return x.result;
 }
 "
@@ -1748,14 +1748,14 @@ type X = ({ a: true } & { b: string }) | ({ a: false } & { c: string });
 function hello1(x: X): string {
   if (x.a === true)
     return x.b;
-else
+  else
     return x.c;
 }
 
 function hello2(x: X): string {
   if (x.a === false)
     return x.c;
-else
+  else
     return x.b;
 }