support spread syntax (#4328)

lib/parse.js

@@ -501,7 +501,16 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
 
     function handle_dot() {
         next();
-        return is_digit(peek().charCodeAt(0)) ? read_num(".") : token("punc", ".");
+        var ch = peek();
+        if (ch == ".") {
+            var op = ".";
+            do {
+                op += ".";
+                next();
+            } while (peek() == ".");
+            return token("operator", op);
+        }
+        return is_digit(ch.charCodeAt(0)) ? read_num(".") : token("punc", ".");
     }
 
     function read_word() {
@@ -1316,6 +1325,12 @@ function parse($TEXT, options) {
             if (allow_trailing_comma && is("punc", closing)) break;
             if (is("punc", ",") && allow_empty) {
                 a.push(new AST_Hole({ start: S.token, end: S.token }));
+            } else if (is("operator", "...") && parser === expression) {
+                a.push(new AST_Spread({
+                    start: S.token,
+                    expression: (next(), parser()),
+                    end: prev(),
+                }));
             } else {
                 a.push(parser());
             }
@@ -1343,6 +1358,15 @@ function parse($TEXT, options) {
             // allow trailing comma
             if (!options.strict && is("punc", "}")) break;
             var start = S.token;
+            if (is("operator", "...")) {
+                next();
+                a.push(new AST_Spread({
+                    start: start,
+                    expression: expression(false),
+                    end: prev(),
+                }));
+                continue;
+            }
             var key = as_property_key();
             if (is("punc", "(")) {
                 var func_start = S.token;