From cb45886512a04697025ca901670e63063064a945 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 16 May 2017 19:59:05 +0800
Subject: [PATCH] export `TreeTransformer` (#1950)

- link to existing documentation on `TreeWalker` & `TreeTransformer`
- fix Travis build failures

fixes #1949
---
 .travis.yml      | 1 -
 README.md        | 6 ++++++
 tools/exports.js | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 06929a34..cdee4301 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,4 @@
 language: node_js
-before_install: "npm install -g npm"
 node_js:
     - "0.10"
     - "0.12"
diff --git a/README.md b/README.md
index adae5794..52bf4267 100644
--- a/README.md
+++ b/README.md
@@ -780,6 +780,12 @@ var result = UglifyJS.minify(ast, {
 // result.code contains the minified code in string form.
 ```
 
+### Working with Uglify AST
+
+Transversal and transformation of the native AST can be performed through
+[`TreeWalker`](http://lisperator.net/uglifyjs/walk) and
+[`TreeTransformer`](http://lisperator.net/uglifyjs/transform) respectively.
+
 ### ESTree / SpiderMonkey AST
 
 UglifyJS has its own abstract syntax tree format; for
diff --git a/tools/exports.js b/tools/exports.js
index 0ffff65e..e08296f3 100644
--- a/tools/exports.js
+++ b/tools/exports.js
@@ -1,4 +1,5 @@
 exports["Dictionary"] = Dictionary;
 exports["TreeWalker"] = TreeWalker;
+exports["TreeTransformer"] = TreeTransformer;
 exports["minify"] = minify;
 exports["_push_uniq"] = push_uniq;