support `import` statements (#4646)

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 7e113ecc..f7151441 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -70,6 +70,7 @@ function Compressor(options, false_by_default) {
         hoist_vars      : false,
         ie8             : false,
         if_return       : !false_by_default,
+        imports         : !false_by_default,
         inline          : !false_by_default,
         join_vars       : !false_by_default,
         keep_fargs      : false_by_default,
@@ -6081,6 +6082,10 @@ merge(Compressor.prototype, {
                 scope = save_scope;
                 return node;
             }
+            if (node instanceof AST_SymbolImport) {
+                if (!compressor.option("imports") || node.definition().id in in_use_ids) return node;
+                return in_list ? List.skip : null;
+            }
         }, function(node, in_list) {
             if (node instanceof AST_BlockStatement) {
                 return trim_block(node, in_list);