From 9637f51b6865d0987dcd950bc7113c871ca6cb3c Mon Sep 17 00:00:00 2001 From: Dan Date: Mon, 5 Feb 2018 08:00:23 +0100 Subject: change `undefined == x` to `null == x` (#2882) fixes #2871 --- lib/compress.js | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/compress.js b/lib/compress.js index 321ee5fc..a48d0c9a 100644 --- a/lib/compress.js +++ b/lib/compress.js @@ -4790,6 +4790,7 @@ merge(Compressor.prototype, { if (compressor.option("comparisons")) switch (self.operator) { case "===": case "!==": + var is_strict_comparison = true; if ((self.left.is_string(compressor) && self.right.is_string(compressor)) || (self.left.is_number(compressor) && self.right.is_number(compressor)) || (self.left.is_boolean() && self.right.is_boolean()) || @@ -4799,8 +4800,12 @@ merge(Compressor.prototype, { // XXX: intentionally falling down to the next case case "==": case "!=": + // void 0 == x => null == x + if (!is_strict_comparison && is_undefined(self.left, compressor)) { + self.left = make_node(AST_Null, self.left); + } // "undefined" == typeof x => undefined === x - if (compressor.option("typeofs") + else if (compressor.option("typeofs") && self.left instanceof AST_String && self.left.value == "undefined" && self.right instanceof AST_UnaryPrefix -- cgit v1.2.3