0.22.0

CHANGELOG.md

@@ -1,3 +1,38 @@
+# 0.22.0
+
+[link](https://github.com/jlongster/prettier/compare/0.21.0...0.22.0)
+
+* Run 0.21.0 (#876)
+* Fix paren removal on UnionTypeAnnotation (#878)
+* Fix typo (#891)
+* Ensure no parens for JSX inside of an ArrayExpression (#895)
+* Fix object expression in arrow function expression (#897)
+* Fix unprinted comments in destructuring (#898)
+* Fix bug with importing empty type (#904)
+* Fix broken export comment (#899)
+* Add CLI Example to Readme (#909)
+* Fix 0.5e0 (#911)
+* Fix binary expression instanceof in arrow function expression (#913)
+* Improve readme CLI usage example (#910)
+* Do not break long it/test calls when template literal (#893)
+* Update lint-staged docs to use husky for less config. (#923)
+* Fix files with comments only (#813)
+* Update README.md (#928)
+* Fix binary op as body in arrow expression (#921)
+* cleanup needsParens (#935)
+* [JSX] Break if opening element breaks (#942)
+* Parenthesize function expressions in expression position (#941)
+* update the README to add a pre-commit hook (#944)
+* Fix #951: properly parenthesize ** expressions (#952)
+* [WIP] TypeScript Parser (#915)
+* Do not break long `describe` calls (#953)
+* Recursively find leading comments inside ReturnStatements (#955)
+* Fix `in` inside of a for in a nested way (#954)
+* Make comments around empty parenthesis be inside (#957)
+* Stabilize comment after object label (#958)
+* Inline BinaryExpressions inside JSXExpression (#965)
+* Only allow same-line arrow-less body for explicit nodes (#966)
+
 # 0.21.0
 
 [link](https://github.com/jlongster/prettier/compare/0.20.0...0.21.0)

docs/prettier.min.js

@@ -8987,7 +8987,8 @@ var PRECEDENCE = {};
   ["<", ">", "<=", ">=", "in", "instanceof"],
   [">>", "<<", ">>>"],
   ["+", "-"],
-  ["*", "/", "%", "**"]
+  ["*", "/", "%"],
+  ["**"]
 ].forEach(function(tier, i) {
   tier.forEach(function(op) {
     PRECEDENCE[op] = i;
@@ -9078,7 +9079,7 @@ function getSortedChildNodes(node, text, resultArray) {
 
   if (!resultArray) {
     Object.defineProperty(node, childNodesCacheKey, {
-      value: resultArray = [],
+      value: (resultArray = []),
       enumerable: false
     });
   }
@@ -9152,24 +9153,38 @@ function attach(comments, ast, text, options) {
 
   var tiesToBreak = [];
 
-  comments.forEach(function(comment) {
+  comments.forEach((comment, i) => {
     decorateComment(ast, comment, text);
 
     const precedingNode = comment.precedingNode;
     const enclosingNode = comment.enclosingNode;
     const followingNode = comment.followingNode;
 
+    const isLastComment = comments.length - 1 === i;
+
     if (util.hasNewline(text, locStart(comment), { backwards: true })) {
       // If a comment exists on its own line, prefer a leading comment.
       // We also need to check if it's the first line of the file.
       if (
-        handleLastFunctionArgComments(precedingNode, enclosingNode, followingNode, comment) ||
+        handleLastFunctionArgComments(
+          precedingNode,
+          enclosingNode,
+          followingNode,
+          comment
+        ) ||
         handleMemberExpressionComments(enclosingNode, followingNode, comment) ||
         handleIfStatementComments(enclosingNode, followingNode, comment) ||
         handleTryStatementComments(enclosingNode, followingNode, comment) ||
-        handleImportSpecifierComments(enclosingNode, comment) ||
         handleClassComments(enclosingNode, comment) ||
-        handleUnionTypeComments(precedingNode, enclosingNode, followingNode, comment)
+        handleImportSpecifierComments(enclosingNode, comment) ||
+        handleObjectPropertyComments(enclosingNode, comment) ||
+        handleUnionTypeComments(
+          precedingNode,
+          enclosingNode,
+          followingNode,
+          comment
+        ) ||
+        handleOnlyComments(enclosingNode, ast, comment, isLastComment)
       ) {
         // We're good
       } else if (followingNode) {
@@ -9194,8 +9209,11 @@ function attach(comments, ast, text, options) {
         ) ||
         handleImportSpecifierComments(enclosingNode, comment) ||
         handleTemplateLiteralComments(enclosingNode, comment) ||
+        handleClassComments(enclosingNode, comment) ||
         handleCallExpressionComments(precedingNode, enclosingNode, comment) ||
-        handleClassComments(enclosingNode, comment)
+        handlePropertyComments(enclosingNode, comment) ||
+        handleExportNamedDeclarationComments(enclosingNode, comment) ||
+        handleOnlyComments(enclosingNode, ast, comment, isLastComment)
       ) {
         // We're good
       } else if (precedingNode) {
@@ -9213,9 +9231,10 @@ function attach(comments, ast, text, options) {
     } else {
       if (
         handleIfStatementComments(enclosingNode, followingNode, comment) ||
-        handleObjectProperty(enclosingNode, precedingNode, comment) ||
+        handleObjectPropertyAssignment(enclosingNode, precedingNode, comment) ||
         handleTemplateLiteralComments(enclosingNode, comment) ||
-        handleFunctionDeclarationComments(enclosingNode, comment)
+        handleCommentInEmptyParens(enclosingNode, comment) ||
+        handleOnlyComments(enclosingNode, ast, comment, isLastComment)
       ) {
         // We're good
       } else if (precedingNode && followingNode) {
@@ -9439,7 +9458,7 @@ function handleConditionalExpressionComments(
   return false;
 }
 
-function handleObjectProperty(enclosingNode, precedingNode, comment) {
+function handleObjectPropertyAssignment(enclosingNode, precedingNode, comment) {
   if (
     enclosingNode &&
     (enclosingNode.type === "ObjectProperty" ||
@@ -9468,35 +9487,61 @@ function handleTemplateLiteralComments(enclosingNode, comment) {
   return false;
 }
 
-function handleFunctionDeclarationComments(enclosingNode, comment) {
+function handleCommentInEmptyParens(enclosingNode, comment) {
   // Only add dangling comments to fix the case when no params are present,
   // i.e. a function without any argument.
   if (
     enclosingNode &&
-    enclosingNode.type === "FunctionDeclaration" &&
+    (((enclosingNode.type === "FunctionDeclaration" ||
-    enclosingNode.params.length === 0
+      enclosingNode.type === "FunctionExpression" ||
+      enclosingNode.type === "ArrowFunctionExpression" ||
+      enclosingNode.type === "ClassMethod" ||
+      enclosingNode.type === "ObjectMethod") &&
+    enclosingNode.params.length === 0) ||
+    (enclosingNode.type === "CallExpression" &&
+      enclosingNode.arguments.length === 0))
   ) {
     addDanglingComment(enclosingNode, comment);
     return true;
   }
+  if (enclosingNode &&
+    (enclosingNode.type === "MethodDefinition" &&
+      enclosingNode.value.params.length === 0)) {
+    addDanglingComment(enclosingNode.value, comment);
+    return true;
+  }
   return false;
 }
 
-function handleLastFunctionArgComments(precedingNode, enclosingNode, followingNode, comment) {
+function handleLastFunctionArgComments(
+  precedingNode,
+  enclosingNode,
+  followingNode,
+  comment
+) {
   // Type definitions functions
-  if (precedingNode && precedingNode.type === 'FunctionTypeParam' &&
+  if (
-    enclosingNode && enclosingNode.type === 'FunctionTypeAnnotation' &&
+    precedingNode &&
-    followingNode && followingNode.type !== 'FunctionTypeParam') {
+    precedingNode.type === "FunctionTypeParam" &&
+    enclosingNode &&
+    enclosingNode.type === "FunctionTypeAnnotation" &&
+    followingNode &&
+    followingNode.type !== "FunctionTypeParam"
+  ) {
     addTrailingComment(precedingNode, comment);
     return true;
   }
 
   // Real functions
-  if (precedingNode && precedingNode.type === 'Identifier' &&
+  if (
-    enclosingNode && (
+    precedingNode &&
-      enclosingNode.type === 'ArrowFunctionExpression' ||
+    precedingNode.type === "Identifier" &&
-      enclosingNode.type === 'FunctionExpression') &&
+    enclosingNode &&
-    followingNode && followingNode.type !== 'Identifier') {
+    (enclosingNode.type === "ArrowFunctionExpression" ||
+      enclosingNode.type === "FunctionExpression") &&
+    followingNode &&
+    followingNode.type !== "Identifier"
+  ) {
     addTrailingComment(precedingNode, comment);
     return true;
   }
@@ -9523,26 +9568,93 @@ function handleImportSpecifierComments(enclosingNode, comment) {
   return false;
 }
 
+function handleObjectPropertyComments(enclosingNode, comment) {
+  if (enclosingNode && enclosingNode.type === "ObjectProperty") {
+    addLeadingComment(enclosingNode, comment);
+    return true;
+  }
+  return false;
+}
+
 function handleCallExpressionComments(precedingNode, enclosingNode, comment) {
-  if (enclosingNode && enclosingNode.type === "CallExpression" &&
+  if (
-      precedingNode && enclosingNode.callee === precedingNode &&
+    enclosingNode &&
-      enclosingNode.arguments.length > 0) {
+    enclosingNode.type === "CallExpression" &&
+    precedingNode &&
+    enclosingNode.callee === precedingNode &&
+    enclosingNode.arguments.length > 0
+  ) {
     addLeadingComment(enclosingNode.arguments[0], comment);
     return true;
   }
   return false;
 }
 
-function handleUnionTypeComments(precedingNode, enclosingNode, followingNode, comment) {
+function handleUnionTypeComments(
-  if (enclosingNode && enclosingNode.type === 'UnionTypeAnnotation' &&
+  precedingNode,
-      precedingNode && precedingNode.type === 'ObjectTypeAnnotation' &&
+  enclosingNode,
-      followingNode && followingNode.type === 'ObjectTypeAnnotation') {
+  followingNode,
+  comment
+) {
+  if (
+    enclosingNode &&
+    enclosingNode.type === "UnionTypeAnnotation" &&
+    precedingNode &&
+    precedingNode.type === "ObjectTypeAnnotation" &&
+    followingNode &&
+    followingNode.type === "ObjectTypeAnnotation"
+  ) {
     addTrailingComment(precedingNode, comment);
     return true;
   }
   return false;
 }
 
+function handlePropertyComments(enclosingNode, comment) {
+  if (
+    enclosingNode && (
+      enclosingNode.type === "Property" ||
+      enclosingNode.type === "ObjectProperty"
+    )
+  ) {
+    addLeadingComment(enclosingNode, comment);
+    return true;
+  }
+  return false;
+}
+
+function handleExportNamedDeclarationComments(enclosingNode, comment) {
+  if (enclosingNode && enclosingNode.type === "ExportNamedDeclaration") {
+    addLeadingComment(enclosingNode, comment);
+    return true;
+  }
+  return false;
+}
+
+function handleOnlyComments(enclosingNode, ast, comment, isLastComment) {
+  // With Flow the enclosingNode is undefined so use the AST instead.
+  if (ast && ast.body && ast.body.length === 0) {
+    if (isLastComment) {
+      addDanglingComment(ast, comment);
+    } else {
+      addLeadingComment(ast, comment);
+    }
+    return true;
+  } else if (
+    enclosingNode && enclosingNode.type === 'Program' &&
+    enclosingNode.body.length === 0 && enclosingNode.directives &&
+    enclosingNode.directives.length === 0
+  ) {
+    if (isLastComment) {
+      addDanglingComment(enclosingNode, comment);
+    } else {
+      addLeadingComment(enclosingNode, comment);
+    }
+    return true;
+  }
+  return false;
+}
+
 function printComment(commentPath) {
   const comment = commentPath.getValue();
   comment.printed = true;
@@ -9716,7 +9828,7 @@ function printComments(path, print, options) {
 var comments$1 = { attach, printComments, printDanglingComments };
 
 var name = "prettier";
-var version$2 = "0.21.0";
+var version$2 = "0.22.0";
 var description = "Prettier is an opinionated JavaScript formatter";
 var bin = {"prettier":"./bin/prettier.js"};
 var repository = {"type":"git","url":"git+https://github.com/jlongster/prettier.git"};
@@ -9725,7 +9837,7 @@ var license = "MIT";
 var bugs = {"url":"https://github.com/jlongster/prettier/issues"};
 var main$2 = "./index.js";
 var dependencies = {"ast-types":"0.9.4","babel-code-frame":"6.22.0","babylon":"6.15.0","chalk":"1.1.3","esutils":"2.0.2","flow-parser":"0.40.0","get-stdin":"5.0.1","glob":"7.1.1","jest-validate":"19.0.0","minimist":"1.2.0"};
-var devDependencies = {"diff":"3.2.0","jest":"19.0.1","rollup":"0.41.1","rollup-plugin-commonjs":"7.0.0","rollup-plugin-json":"2.1.0","rollup-plugin-node-builtins":"2.0.0","rollup-plugin-node-globals":"1.1.0","rollup-plugin-node-resolve":"2.0.0"};
+var devDependencies = {"diff":"3.2.0","jest":"19.0.1","rollup":"0.41.1","rollup-plugin-commonjs":"7.0.0","rollup-plugin-json":"2.1.0","rollup-plugin-node-builtins":"2.0.0","rollup-plugin-node-globals":"1.1.0","rollup-plugin-node-resolve":"2.0.0","typescript":"2.2.1","typescript-eslint-parser":"git://github.com/eslint/typescript-eslint-parser.git#215a012ec4d272939fa5a57d0231d22fb7f7a9e0"};
 var scripts = {"test":"jest","format":"./bin/prettier.js --write","format:single":"npm run format -- src/printer.js","format:all":"npm run format -- index.js src/*.js bin/*.js","build:docs":"rollup -c docs/rollup.config.js"};
 var jest = {"setupFiles":["<rootDir>/tests_config/run_spec.js"],"testRegex":"jsfmt\\.spec\\.js$","testPathIgnorePatterns":["tests/new_react","tests/more_react"]};
 var _package = {
@@ -9787,7 +9899,7 @@ FastPath$1.from = function(obj) {
     // lightweight FastPath [..., name, value] stacks.
     var copy = Object.create(FastPath$1.prototype);
     var stack = [obj.value];
-    for (var pp; pp = obj.parentPath; obj = pp)
+    for (var pp; (pp = obj.parentPath); obj = pp)
       stack.push(obj.name, pp.value);
     copy.stack = stack.reverse();
     return copy;
@@ -9994,20 +10106,17 @@ FPp.needsParens = function(assumeExpressionContext) {
     return true;
   }
 
-  // The left-hand side of the ** exponentiation operator must always
-  // be parenthesized unless it's an ident or literal
   if (
-    parent.type === "BinaryExpression" &&
+    parent.type === "ArrowFunctionExpression" && parent.body === node && startsWithNoLookaheadToken(node, /* forbidFunctionAndClass */ false)
-    parent.operator === "**" &&
+    || parent.type === "ExpressionStatement" && startsWithNoLookaheadToken(node, /* forbidFunctionAndClass */ true)
-    parent.left === node &&
-    node.type !== "Identifier" &&
-    node.type !== "Literal" &&
-    node.type !== "NumericLiteral"
   ) {
     return true;
   }
 
   switch (node.type) {
+    case "CallExpression":
+      return false;
+
     case "SpreadElement":
     case "SpreadProperty":
       return parent.type === "MemberExpression" &&
@@ -10015,26 +10124,12 @@ FPp.needsParens = function(assumeExpressionContext) {
         parent.object === node;
 
     case "UpdateExpression":
-      switch (parent.type) {
+      if (parent.type === "UnaryExpression") {
-        case "MemberExpression":
+        return node.prefix &&
-          return name === "object" && parent.object === node;
-
-        case "TaggedTemplateExpression":
-        case "NewExpression":
-          return true;
-
-        case "UnaryExpression":
-          if (
-            node.prefix &&
           ((node.operator === "++" && parent.operator === "+") ||
-              (node.operator === "--" && parent.operator === "-"))
+              (node.operator === "--" && parent.operator === "-"));
-          ) {
-            return true;
       }
-
+      // else fall through
-          return false;
-      }
-
     case "UnaryExpression":
       switch (parent.type) {
         case "UnaryExpression":
@@ -10043,21 +10138,40 @@ FPp.needsParens = function(assumeExpressionContext) {
 
         case "MemberExpression":
           return name === "object" && parent.object === node;
+
+        case "TaggedTemplateExpression":
+          return true;
+
+        case "NewExpression":
+        case "CallExpression":
+          return name === "callee" && parent.callee == node;
+
+        case "BinaryExpression":
+          return parent.operator === "**" && name === "left";
+
+        default:
+          return false;
       }
 
     case "BinaryExpression":
-      if (
+      const isLeftOfAForStatement = node => {
-        node.operator === "in" &&
+        let i = 0;
-        parent.type === "ForStatement" &&
+        while (node) {
-        parent.init === node
+          let parent = this.getParentNode(i++);
-      ) {
+          if (!parent) {
+            return false;
+          }
+          if (parent.type === "ForStatement" && parent.init === node) {
             return true;
           }
-
+          node = parent;
-      if (node.operator === "in" && parent.type === "AssignmentExpression") {
+        }
+        return false;
+      };
+      if (node.operator === "in" && isLeftOfAForStatement(node)) {
         return true;
       }
-
+      // else fall through
     case "LogicalExpression":
       switch (parent.type) {
         case "CallExpression":
@@ -10088,6 +10202,10 @@ FPp.needsParens = function(assumeExpressionContext) {
             return true;
           }
 
+          if (no === "**" && po === "**") {
+            return name === "left";
+          }
+
           if (pp === np && name === "right") {
             assert$6.strictEqual(parent.right, node);
             return true;
@@ -10122,6 +10240,7 @@ FPp.needsParens = function(assumeExpressionContext) {
       if (parent.type === "UnaryExpression") {
         return true;
       }
+      // else fall through
     case "AwaitExpression":
       switch (parent.type) {
         case "TaggedTemplateExpression":
@@ -10148,7 +10267,8 @@ FPp.needsParens = function(assumeExpressionContext) {
 
     case "IntersectionTypeAnnotation":
     case "UnionTypeAnnotation":
-      return parent.type === "NullableTypeAnnotation" ||
+      return parent.type === "ArrayTypeAnnotation" ||
+        parent.type === "NullableTypeAnnotation" ||
         parent.type === "IntersectionTypeAnnotation" ||
         parent.type === "UnionTypeAnnotation";
 
@@ -10167,21 +10287,15 @@ FPp.needsParens = function(assumeExpressionContext) {
         parent.object === node;
 
     case "AssignmentExpression":
-      if (
+      if (parent.type === "ArrowFunctionExpression" && parent.body === node) {
-        parent.type === "ArrowFunctionExpression" &&
-        parent.body === node
-      ) {
         return node.left.type === "ObjectPattern";
-      }
+      } else if (
-      if (parent.type === "ForStatement" &&
+        parent.type === "ForStatement" &&
-        (parent.init === node || parent.update === node)) {
+        (parent.init === node || parent.update === node)
-        return false;
+      ) {
-      }
-      if (parent.type === "ExpressionStatement") {
-        if (node.left.type === "ObjectPattern") {
-          return true;
-        }
         return false;
+      } else if (parent.type === "ExpressionStatement") {
+        return node.left.type === "ObjectPattern";
       }
       return true;
 
@@ -10209,85 +10323,53 @@ FPp.needsParens = function(assumeExpressionContext) {
           return name === "object" && parent.object === node;
 
         default:
-          return n$2.ObjectPattern.check(node.left) && this.firstInStatement();
+          return false;
       }
 
     case "FunctionExpression":
-    case "ArrowFunctionExpression":
-      if (parent.type === "CallExpression" && name === "callee") {
-        return true;
-      }
-
       switch (parent.type) {
-        case "ConditionalExpression":
+        case "CallExpression":
-          if (parent.test === node) {
+          return name === "callee"; // Not strictly necessary, but it's clearer to the reader if IIFEs are wrapped in parentheses.
-            return true;
-          }
-          return false;
-
-        case "ExportDefaultDeclaration":
-          if (
-            node.type === "ArrowFunctionExpression" ||
-            node.type === "FunctionDeclaration"
-          ) {
-            return false;
-          }
-          return true;
-
-        case "ExpressionStatement":
-        case "MemberExpression":
         case "TaggedTemplateExpression":
-        case "UnaryExpression":
+          return true; // This is basically a kind of IIFE.
+        case "ExportDefaultDeclaration":
           return true;
+        default:
+          return false;
+      }
+
+    case "ArrowFunctionExpression":
+      switch (parent.type) {
+        case "CallExpression":
+          return name === "callee";
 
         case "NewExpression":
           return name === "callee";
 
+        case "MemberExpression":
+          return name === "object";
+
+        case "BindExpression":
+        case "TaggedTemplateExpression":
+        case "UnaryExpression":  
         case "LogicalExpression":
-          return node.type === "ArrowFunctionExpression";
+        case "BinaryExpression":
+          return true;
+
+        case "ConditionalExpression":
+          return name === "test";
 
         default:
-          return isBinary(parent);
+          return false;
       }
 
     case "ClassExpression":
-      switch (parent.type) {
+      return parent.type === "ExportDefaultDeclaration";
-        case "TaggedTemplateExpression":
-        case "BinaryExpression":
-        case "ExportDefaultDeclaration":
-        case "ExpressionStatement":
-          return true;
-        case "CallExpression":
-          if (parent.callee === node) {
-            return true;
-          }
-        case "MemberExpression":
-          return name === "object" && parent.object === node;
-        case "ConditionalExpression":
-          if (parent.test === node) {
-            return true;
-          }
-      }
-
-      return false;
-
-    case "ObjectExpression":
-      if (parent.type === "ArrowFunctionExpression" && name === "body") {
-        return true;
-      }
-      if (parent.type === "TaggedTemplateExpression") {
-        return true;
-      }
-      if (parent.type === "MemberExpression") {
-        return name === "object" && parent.object === node;
-      }
 
     case "StringLiteral":
-      if (parent.type === "ExpressionStatement") {
+      return parent.type === "ExpressionStatement"; // To avoid becoming a directive
-        return true;
   }
 
-    default:
   if (
     parent.type === "NewExpression" &&
     name === "callee" &&
@@ -10295,22 +10377,10 @@ FPp.needsParens = function(assumeExpressionContext) {
   ) {
     return containsCallExpression(node);
   }
-  }
-
-  if (
-    assumeExpressionContext !== true &&
-    !this.canBeFirstInStatement() &&
-    this.firstInStatement()
-  )
-    return true;
 
   return false;
 };
 
-function isBinary(node) {
-  return n$2.BinaryExpression.check(node) || n$2.LogicalExpression.check(node);
-}
-
 function containsCallExpression(node) {
   if (n$2.CallExpression.check(node)) {
     return true;
@@ -10329,86 +10399,50 @@ function containsCallExpression(node) {
   return false;
 }
 
-FPp.canBeFirstInStatement = function() {
+// Tests if an expression starts with `{`, or (if forbidFunctionAndClass holds) `function` or `class`.
-  var node = this.getNode();
+// Will be overzealous if there's already necessary grouping parentheses.
-  return !n$2.FunctionExpression.check(node) &&
+function startsWithNoLookaheadToken(node, forbidFunctionAndClass) {
-    !n$2.ObjectExpression.check(node) &&
+  node = getLeftMost(node);
-    !n$2.ClassExpression.check(node) &&
+  switch (node.type) {
-    !(n$2.AssignmentExpression.check(node) && n$2.ObjectPattern.check(node.left));
+    case "FunctionExpression":
-};
+    case "ClassExpression":
-
+      return forbidFunctionAndClass;
-FPp.firstInStatement = function() {
+    case "ObjectExpression":
-  var s = this.stack;
-  var parentName, parent;
-  var childName, child;
-
-  for (var i = s.length - 1; i >= 0; i -= 2) {
-    if (n$2.Node.check(s[i])) {
-      childName = parentName;
-      child = parent;
-      parentName = s[i - 1];
-      parent = s[i];
-    }
-
-    if (!parent || !child) {
-      continue;
-    }
-
-    if (
-      n$2.BlockStatement.check(parent) && parentName === "body" && childName === 0
-    ) {
-      assert$6.strictEqual(parent.body[0], child);
       return true;
-    }
+    case "MemberExpression":
-
+      return startsWithNoLookaheadToken(node.object, forbidFunctionAndClass);
-    if (n$2.ExpressionStatement.check(parent) && childName === "expression") {
+    case "TaggedTemplateExpression":
-      assert$6.strictEqual(parent.expression, child);
+      if (node.tag.type === "FunctionExpression") {
-      return true;
+        // IIFEs are always already parenthesized
-    }
-
-    if (
-      n$2.SequenceExpression.check(parent) &&
-      parentName === "expressions" &&
-      childName === 0
-    ) {
-      assert$6.strictEqual(parent.expressions[0], child);
-      continue;
-    }
-
-    if (n$2.CallExpression.check(parent) && childName === "callee") {
-      assert$6.strictEqual(parent.callee, child);
-      continue;
-    }
-
-    if (n$2.MemberExpression.check(parent) && childName === "object") {
-      assert$6.strictEqual(parent.object, child);
-      continue;
-    }
-
-    if (n$2.ConditionalExpression.check(parent) && childName === "test") {
-      assert$6.strictEqual(parent.test, child);
-      continue;
-    }
-
-    if (isBinary(parent) && childName === "left") {
-      assert$6.strictEqual(parent.left, child);
-      continue;
-    }
-
-    if (
-      n$2.UnaryExpression.check(parent) &&
-      !parent.prefix &&
-      childName === "argument"
-    ) {
-      assert$6.strictEqual(parent.argument, child);
-      continue;
-    }
-
         return false;
       }
+      return startsWithNoLookaheadToken(node.tag, forbidFunctionAndClass);
+    case "CallExpression":
+      if (node.callee.type === "FunctionExpression") {
+        // IIFEs are always already parenthesized
+        return false;
+      }
+      return startsWithNoLookaheadToken(node.callee, forbidFunctionAndClass);
+    case "ConditionalExpression":
+      return startsWithNoLookaheadToken(node.test, forbidFunctionAndClass);
+    case "UpdateExpression":
+      return !node.prefix && startsWithNoLookaheadToken(node.argument, forbidFunctionAndClass);
+    case "BindExpression":
+      return node.object && startsWithNoLookaheadToken(node.object, forbidFunctionAndClass);
+    case "SequenceExpression":
+      return startsWithNoLookaheadToken(node.expressions[0], forbidFunctionAndClass)
+    default:
+      return false;
+  }
+}
 
-  return true;
+function getLeftMost(node) {
-};
+  if (node.left) {
+    return getLeftMost(node.left);
+  } else {
+    return node;
+  }
+}
 
 var fastPath = FastPath$1;
 
@@ -10751,25 +10785,18 @@ function genericPrintNoParens(path, options, print) {
         n.body.type === "ArrayExpression" ||
         n.body.type === "ObjectExpression" ||
         n.body.type === "JSXElement" ||
-        n.body.type === "BlockStatement"
+        n.body.type === "BlockStatement" ||
+        n.body.type === "TaggedTemplateExpression" ||
+        n.body.type === "TemplateElement"
       ) {
         return group$1(collapsed);
       }
 
-      // These nested groups are a little wonky, but because
-      // `conditionalGroup` suppresses break propagation, we want to
-      // re-propagate it. We still want to allow the printer to choose
-      // the more collapsed version, but still break parents if there
-      // are any hard breaks in the content.
       return group$1(
-        conditionalGroup$1([
-          collapsed,
         concat$2([
           concat$2(parts),
           group$1(indent$2(options.tabWidth, concat$2([line$1, body])))
         ])
-        ]),
-        { shouldBreak: willBreak$2(body) }
       );
     case "MethodDefinition":
       if (n.static) {
@@ -10935,6 +10962,8 @@ function genericPrintNoParens(path, options, print) {
         }
 
         fromParts.push(grouped.length === 0 ? line$1 : " ", "from ");
+      } else if (n.importKind && n.importKind === "type") {
+        parts.push("{} from ");
       }
 
       fromParts.push(path.call(print, "source"), ";");
@@ -11013,11 +11042,8 @@ function genericPrintNoParens(path, options, print) {
     case "ReturnStatement":
       parts.push("return");
 
-      if (
+      if (n.argument) {
-        n.argument &&
+        if (returnArgumentHasLeadingComment(options, n.argument)) {
-        n.argument.comments &&
-        n.argument.comments.some(comment => comment.leading)
-      ) {
           parts.push(
             concat$2([
               " (",
@@ -11029,9 +11055,10 @@ function genericPrintNoParens(path, options, print) {
               ")"
             ])
           );
-      } else if (n.argument) {
+        } else {
           parts.push(" ", path.call(print, "argument"));
         }
+      }
 
       parts.push(";");
 
@@ -11039,13 +11066,20 @@ function genericPrintNoParens(path, options, print) {
     case "CallExpression": {
       if (
         // We want to keep require calls as a unit
-        n.callee.type === "Identifier" && n.callee.name === "require" ||
+        (n.callee.type === "Identifier" && n.callee.name === "require") ||
-        // `it('long name', () => {` should not break
+        // Keep test declarations on a single line
-        (n.callee.type === "Identifier" && (
+        // e.g. `it('long name', () => {`
-          n.callee.name === "it" || n.callee.name === "test") &&
+        (n.callee.type === "Identifier" &&
+          (n.callee.name === "it" ||
+            n.callee.name === "test" ||
+            n.callee.name === "describe") &&
           n.arguments.length === 2 &&
-          (n.arguments[0].type === "StringLiteral" || n.arguments[0].type === "Literal" && typeof n.arguments[0].value === "string") &&
+          (n.arguments[0].type === "StringLiteral" ||
-          (n.arguments[1].type === "FunctionExpression" || n.arguments[1].type === "ArrowFunctionExpression") &&
+            n.arguments[0].type === "TemplateLiteral" ||
+            (n.arguments[0].type === "Literal" &&
+              typeof n.arguments[0].value === "string")) &&
+          (n.arguments[1].type === "FunctionExpression" ||
+            n.arguments[1].type === "ArrowFunctionExpression") &&
           n.arguments[1].params.length <= 1)
       ) {
         return concat$2([
@@ -11669,7 +11703,7 @@ function genericPrintNoParens(path, options, print) {
         n.expression.type === "JSXEmptyExpression" ||
         (parent.type === "JSXElement" &&
           (n.expression.type === "ConditionalExpression" ||
-            n.expression.type === "LogicalExpression"));
+            isBinaryish(n.expression)));
 
       if (shouldInline) {
         return group$1(
@@ -11737,7 +11771,11 @@ function genericPrintNoParens(path, options, print) {
     case "JSXText":
       throw new Error("JSXTest should be handled by JSXElement");
     case "JSXEmptyExpression":
-      return comments$3.printDanglingComments(path, options, /* sameIndent */ true);
+      return comments$3.printDanglingComments(
+        path,
+        options,
+        /* sameIndent */ true
+      );
     case "TypeAnnotatedIdentifier":
       return concat$2([
         path.call(print, "annotation"),
@@ -12030,7 +12068,7 @@ function genericPrintNoParens(path, options, print) {
 
       const parent = path.getParentNode();
       // If there's a leading comment, the parent is doing the indentation
-      const shouldIndent = !(parent.type === 'TypeAlias' &&
+      const shouldIndent = !(parent.type === "TypeAlias" &&
         hasLeadingOwnLineComment(options.originalText, n));
 
       const token = isIntersection ? "&" : "|";
@@ -12355,7 +12393,11 @@ function printArgumentsList(path, options, print) {
   var printed = path.map(print, "arguments");
 
   if (printed.length === 0) {
-    return "()";
+    return concat$2([
+      "(",
+      comments$3.printDanglingComments(path, options, /* sameIndent */ true),
+      ")"
+    ]);
   }
 
   const args = path.getValue().arguments;
@@ -12443,8 +12485,7 @@ function printFunctionParams(path, print, options) {
 
   const lastParam = util$4.getLast(path.getValue().params);
   const canHaveTrailingComma = !(lastParam &&
-    lastParam.type === "RestElement") &&
+    lastParam.type === "RestElement") && !fun.rest;
-    !fun.rest;
 
   // If the parent is a call with the last argument expansion and this is the
   // params of the last argument, we dont want the arguments to break and instead
@@ -12457,9 +12498,11 @@ function printFunctionParams(path, print, options) {
   //   })                    ) => {
   //                         })
   const parent = path.getParentNode();
-  if ((parent.type === "CallExpression" || parent.type === "NewExpression") &&
+  if (
+    (parent.type === "CallExpression" || parent.type === "NewExpression") &&
     util$4.getLast(parent.arguments) === path.getValue() &&
-    shouldGroupLastArg(parent.arguments)) {
+    shouldGroupLastArg(parent.arguments)
+  ) {
     return concat$2(["(", join$2(", ", printed), ")"]);
   }
 
@@ -13009,12 +13052,13 @@ function printJSXElement(path, options, print) {
     assert$5.ok(!n.closingElement);
     return openingLines;
   }
+  // Record any breaks. Should never go from true to false, only false to true.
+  let forcedBreak = willBreak$2(openingLines);
 
   const jsxWhitespace = options.singleQuote
     ? ifBreak$1("{' '}", " ")
     : ifBreak$1('{" "}', " ");
   const children = printJSXChildren(path, options, print, jsxWhitespace);
-  let forcedBreak = false;
 
   // Trim trailing lines, recording if there was a hardline
   let numTrailingHard = 0;
@@ -13119,6 +13163,7 @@ function maybeWrapJSXElementInParens(path, elem, options) {
   if (!parent) return elem;
 
   const NO_WRAP_PARENTS = {
+    ArrayExpression: true,
     JSXElement: true,
     JSXExpressionContainer: true,
     ExpressionStatement: true,
@@ -13170,10 +13215,12 @@ function printBinaryishExpressions(path, parts, print, options, isNested) {
     // is where the rest of the expression will exist. Binary
     // expressions on the right side mean they have a difference
     // precedence level and should be treated as a separate group, so
-    // print them normally.
+    // print them normally. (This doesn't hold for the `**` operator,
+    // which is unique in that it is right-associative.)
     if (
       util$4.getPrecedence(node.left.operator) ===
       util$4.getPrecedence(node.operator)
+      && node.operator !== "**"
     ) {
       // Flatten them out by recursively calling this function. The
       // printed values will all be appended to `parts`.
@@ -13201,8 +13248,7 @@ function printBinaryishExpressions(path, parts, print, options, isNested) {
     // If there's only a single binary expression, we want to create a group
     // in order to avoid having a small right part like -1 be on its own line.
     const parent = path.getParentNode();
-    const shouldGroup =
+    const shouldGroup = parent.type !== node.type &&
-      parent.type !== node.type &&
       node.left.type !== node.type &&
       node.right.type !== node.type;
 
@@ -13323,7 +13369,9 @@ function printNumber(rawNumber) {
   return rawNumber
     .toLowerCase()
     // Remove unnecessary plus and zeroes from scientific notation.
-    .replace(/^([\d.]+e)(?:\+|(-))?0*/, "$1$2")
+    .replace(/^([\d.]+e)(?:\+|(-))?0*(\d)/, "$1$2$3")
+    // Remove unnecessary scientific notation (1e0).
+    .replace(/^([\d.]+)e[+-]?0+$/, "$1")
     // Make sure numbers always start with a digit.
     .replace(/^\./, "0.")
     // Remove trailing dot.
@@ -13348,6 +13396,44 @@ function hasLeadingOwnLineComment(text, node) {
   return res;
 }
 
+// This recurses the return argument, looking for the first token
+// (the leftmost leaf node) and, if it (or its parents) has any
+// leadingComments, returns true (so it can be wrapped in parens).
+function returnArgumentHasLeadingComment(options, argument) {
+  if (hasLeadingOwnLineComment(options.originalText, argument)) {
+    return true;
+  }
+
+  const hasCommentableLeftSide = argument.type === "BinaryExpression" ||
+    argument.type === "LogicalExpression" ||
+    argument.type === "ConditionalExpression" ||
+    argument.type === "CallExpression" ||
+    argument.type === "MemberExpression" ||
+    argument.type === "SequenceExpression" ||
+    argument.type === "TaggedTemplateExpression";
+
+  if (hasCommentableLeftSide) {
+    const getLeftSide = (node) => {
+      if (node.expressions) {
+        return node.expressions[0];
+      }
+      return node.left || node.test || node.callee || node.object || node.tag;
+    };
+
+    let leftMost = argument;
+    let newLeftMost;
+    while (newLeftMost = getLeftSide(leftMost)) {
+      leftMost = newLeftMost;
+
+      if (hasLeadingOwnLineComment(options.originalText, leftMost)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
 // Hack to differentiate between the following two which have the same ast
 // type T = { method: () => void };
 // type T = { method(): void };
@@ -28957,7 +29043,20 @@ function parseWithBabylon(text) {
   });
 }
 
-var parser$1 = { parseWithFlow, parseWithBabylon };
+function parseWithTypeScript(text) {
+    // const parser = require('typescript-eslint-parser')
+    return parser.parse(text, {
+        loc: true,
+        range: true,
+        tokens: true,
+        attachComment: true,
+        ecmaFeatures: {
+            jsx: true,
+        }
+    })
+}
+
+var parser_1 = { parseWithFlow, parseWithBabylon, parseWithTypeScript };
 
 function flattenDoc(doc) {
   if (doc.type === "concat") {
@@ -29071,7 +29170,7 @@ const version = require$$2$11.version;
 const printAstToDoc = printer.printAstToDoc;
 const printDocToString = docPrinter.printDocToString;
 const normalizeOptions = options.normalize;
-const parser = parser$1;
+const parser$1 = parser_1;
 const printDocToDebug = docDebug.printDocToDebug;
 
 function guessLineEnding(text) {
@@ -29083,9 +29182,15 @@ function guessLineEnding(text) {
 }
 
 function parse(text, opts) {
-  const parseFunction = opts.parser === "flow"
+  let parseFunction;
-    ? parser.parseWithFlow
+
-    : parser.parseWithBabylon;
+  if (opts.parser === 'flow') {
+    parseFunction = parser$1.parseWithFlow;
+  } else if (opts.parser === 'typescript') {
+    parseFunction = parser$1.parseWithTypeScript;
+  } else {
+    parseFunction = parser$1.parseWithBabylon;
+  }
 
   try {
     return parseFunction(text);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "prettier",
-  "version": "0.21.0",
+  "version": "0.22.0",
   "description": "Prettier is an opinionated JavaScript formatter",
   "bin": {
     "prettier": "./bin/prettier.js"