improve usability of `global_defs` in `minify()` (#1987)

Use `@key` to `parse()` string value as `AST_Node`.

fixes #1986

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 73ab21f4..a2f8f267 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -87,6 +87,17 @@ function Compressor(options, false_by_default) {
         unused        : !false_by_default,
         warnings      : false,
     }, true);
+    var global_defs = this.options["global_defs"];
+    if (typeof global_defs == "object") for (var key in global_defs) {
+        if (/^@/.test(key) && HOP(global_defs, key)) {
+            var ast = parse(global_defs[key]);
+            if (ast.body.length == 1 && ast.body[0] instanceof AST_SimpleStatement) {
+                global_defs[key.slice(1)] = ast.body[0].body;
+            } else throw new Error(string_template("Can't handle expression: {value}", {
+                value: global_defs[key]
+            }));
+        }
+    }
     var pure_funcs = this.options["pure_funcs"];
     if (typeof pure_funcs == "function") {
         this.pure_funcs = pure_funcs;