fix ie8 option alias

[alexlamsl]

fixes #5102

[kzc]

The PR is not quite right. Legacy ie8 sub-options of output, compress and mangle are not handled correctly. For example, these two commands should produce:

$ echo 'function aaa(t) { return t.default; }' | bin/uglifyjs -O ie8
function aaa(t){return t["default"]}

$ echo 'function aaa(t) { return t.default; }' | bin/uglifyjs -O ie
function aaa(t){return t["default"]}

I suggest something like the following, which also passes npm test:

diff --git a/lib/compress.js b/lib/compress.js
index dc171ae..8f5cbe9 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -72,3 +72,4 @@ function Compressor(options, false_by_default) {
         hoist_vars      : false,
-        ie              : false,
+        ie              : options && options.ie8 || false,
+        ie8             : options && options.ie || false,
         if_return       : !false_by_default,
diff --git a/lib/minify.js b/lib/minify.js
index d3394b4..4a4243a 100644
--- a/lib/minify.js
+++ b/lib/minify.js
@@ -78,4 +78,4 @@ function minify(files, options) {
             enclose: false,
-            ie: false,
-            ie8: false,
+            ie: options && options.ie8 || false,
+            ie8: options && options.ie || false,
             keep_fnames: false,
@@ -99,3 +99,4 @@ function minify(files, options) {
         if (options.annotations !== undefined) set_shorthand("annotations", options, [ "compress", "output" ]);
-        if (options.ie || options.ie8) set_shorthand("ie", options, [ "compress", "mangle", "output" ]);
+        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output" ]);
+        if (options.ie8) set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
         if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
@@ -110,2 +111,3 @@ function minify(files, options) {
                 ie: false,
+                ie8: false,
                 keep_fnames: false,
diff --git a/lib/output.js b/lib/output.js
index 0cf379d..d41f053 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -58,3 +58,4 @@ function OutputStream(options) {
         galio            : false,
-        ie               : false,
+        ie               : options && options.ie8 || false,
+        ie8              : options && options.ie || false,
         indent_level     : 4,
diff --git a/lib/scope.js b/lib/scope.js
index 2219b89..35684b7 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -120,3 +120,4 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         cache: null,
-        ie: false,
+        ie: options && options.ie8 || false,
+        ie8: options && options.ie || false,
     });
@@ -574,3 +575,4 @@ function _default_mangler_options(options) {
         eval        : false,
-        ie          : false,
+        ie          : options && options.ie8 && false,
+        ie8         : options && options.ie && false,
         keep_fnames : false,

[alexlamsl]

That's intentional − I'm only keeping the alias for the top-level option.

[fengmk2]

Temporary fixes by cnpm/bug-versions#147

[kzc]

That's intentional − I'm only keeping the alias for the top-level option.

Why break backwards compatibility when it's so simple to resolve?

[alexlamsl]

Why break backwards compatibility when it's so simple to resolve?

Because only the top-level option is documented for general use.

If you are using the individual sub-options, you are either advanced enough to figure out what happened and delete one character, or you are using it by mistake since you need all of them for proper browser compatibility.

Either case, I am not spraying legacy code all over.