message: Add isGuardClause()
diff: +import { NodePath } from "@babel/traverse";
  import * as t from "@babel/types";
  export * from "@babel/types";
  @@ -5,6 +6,7 @@ export {
  isArrayExpressionElement,
  areAllObjectProperties,
  isUndefinedLiteral,
  + isGuardClause,
  isTemplateExpression,
  templateElement,
  Primitive
  @@ -29,6 +31,10 @@ function isUndefinedLiteral(
  return t.isIdentifier(node, opts) && node.name === "undefined";
  }
  +function isGuardClause(path: NodePath<t.IfStatement>) {
  + return t.isReturnStatement(path.node.consequent);
  +}
  +
  function isTemplateExpression(node: t.Node): node is TemplateExpression {
  return (
  t.isIdentifier(node) ||
  