Fix #269

Shorten most primitives where possible. Also optimize some edge cases.

lib/compress.js

@@ -1620,7 +1620,7 @@ merge(Compressor.prototype, {
                     if (self.args.length != 1) {
                         return make_node(AST_Array, self, {
                             elements: self.args
-                        });
+                        }).transform(compressor);
                     }
                     break;
                   case "Object":
@@ -1634,11 +1634,30 @@ merge(Compressor.prototype, {
                     if (self.args.length == 0) return make_node(AST_String, self, {
                         value: ""
                     });
-                    return make_node(AST_Binary, self, {
+                    if (self.args.length <= 1) return make_node(AST_Binary, self, {
                         left: self.args[0],
                         operator: "+",
                         right: make_node(AST_String, self, { value: "" })
+                    }).transform(compressor);
+                    break;
+                  case "Number":
+                    if (self.args.length == 0) return make_node(AST_Number, self, {
+                        value: 0
                     });
+                    if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
+                        expression: self.args[0],
+                        operator: "+"
+                    }).transform(compressor);
+                  case "Boolean":
+                    if (self.args.length == 0) return make_node(AST_False, self);
+                    if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
+                        expression: make_node(AST_UnaryPrefix, null, {
+                            expression: self.args[0],
+                            operator: "!"
+                        }),
+                        operator: "!"
+                    }).transform(compressor);
+                    break;
                   case "Function":
                     if (all(self.args, function(x){ return x instanceof AST_String })) {
                         // quite a corner-case, but we can handle it:
@@ -1999,6 +2018,16 @@ merge(Compressor.prototype, {
             && self.right.getValue() === "" && self.left instanceof AST_Binary
             && self.left.operator == "+" && self.left.is_string(compressor)) {
             return self.left;
+        } else if (self.operator == "+" && self.right instanceof AST_String
+            && self.right.getValue() === "" && self.left instanceof AST_Binary
+            && self.left.operator == "+" && self.left.right instanceof AST_Number) {
+            return make_node(AST_Binary, self, {
+                left: self.left.left,
+                operator: "+",
+                right: make_node(AST_String, self.right, {
+                    value: String(self.left.right.value)
+                })
+            });
         }
         if (compressor.option("evaluate")) {
             if (self.operator == "+") {

test/compress/issue-269.js

@@ -0,0 +1,68 @@
+issue_269_1: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x),
+			Number(x),
+			Boolean(x),
+
+			String(),
+			Number(),
+			Boolean()
+		);
+	}
+	expect: {
+		f(
+			x + '', +x, !!x,
+			'', 0, false
+		);
+	}
+}
+
+issue_269_dangers: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x, x),
+			Number(x, x),
+			Boolean(x, x)
+		);
+	}
+	expect: {
+		f(String(x, x), Number(x, x), Boolean(x, x));
+	}
+}
+
+issue_269_in_scope: {
+	options = {unsafe: true};
+	input: {
+		var String, Number, Boolean;
+		f(
+			String(x),
+			Number(x, x),
+			Boolean(x)
+		);
+	}
+	expect: {
+		var String, Number, Boolean;
+		f(String(x), Number(x, x), Boolean(x));
+	}
+}
+
+strings_concat: {
+	options = {unsafe: true};
+	input: {
+		f(
+			String(x + 'str'),
+			String('str' + x),
+			String(x + 5)
+		);
+	}
+	expect: {
+		f(
+			x + 'str',
+			'str' + x,
+			x + '5'
+		);
+	}
+}