enhance booleans & evaluate (#5364)

lib/compress.js

@@ -11134,21 +11134,17 @@ Compressor.prototype.compress = function(node) {
         }
         if (in_bool) switch (self.operator) {
           case "+":
-            var ll = self.left.evaluate(compressor);
+            var ev = self.left.evaluate(compressor, true);
-            var rr = self.right.evaluate(compressor);
+            if (ev && typeof ev == "string" || (ev = self.right.evaluate(compressor, true)) && typeof ev == "string") {
-            if (ll && typeof ll == "string") {
                 AST_Node.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
-                return make_sequence(self, [
+                var exprs = [];
-                    self.right,
+                if (self.left.evaluate(compressor) instanceof AST_Node) exprs.push(self.left);
-                    make_node(AST_True, self)
+                if (self.right.evaluate(compressor) instanceof AST_Node) exprs.push(self.right);
-                ]).optimize(compressor);
+                if (exprs.length < 2) {
-            }
+                    exprs.push(make_node(AST_True, self));
-            if (rr && typeof rr == "string") {
+                    return make_sequence(self, exprs).optimize(compressor);
-                AST_Node.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
+                }
-                return make_sequence(self, [
+                self.truthy = true;
-                    self.left,
-                    make_node(AST_True, self)
-                ]).optimize(compressor);
             }
             break;
           case "==":
@@ -11231,20 +11227,15 @@ Compressor.prototype.compress = function(node) {
                     AST_Node.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
                     return make_sequence(self, [ self.left, self.right ]).optimize(compressor);
                 }
-                var rr = self.right.evaluate(compressor);
+                if (!self.right.evaluate(compressor, true)) {
-                if (!rr) {
+                    if (in_bool && !(self.right.evaluate(compressor) instanceof AST_Node)) {
-                    if (in_bool) {
                         AST_Node.warn("Boolean && always false [{file}:{line},{col}]", self.start);
-                        return make_sequence(self, [
+                        return make_sequence(self, [ self.left, make_node(AST_False, self) ]).optimize(compressor);
-                            self.left,
-                            make_node(AST_False, self)
-                        ]).optimize(compressor);
                     } else self.falsy = true;
-                } else if (!(rr instanceof AST_Node)) {
+                } else if ((in_bool || parent.operator == "&&" && parent.left === compressor.self())
-                    if (in_bool || parent.operator == "&&" && parent.left === compressor.self()) {
+                    && !(self.right.evaluate(compressor) instanceof AST_Node)) {
-                        AST_Node.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start);
+                    AST_Node.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start);
-                        return self.left.optimize(compressor);
+                    return self.left.optimize(compressor);
-                    }
                 }
                 // (x || false) && y ---> x ? y : false
                 if (self.left.operator == "||") {
@@ -11279,25 +11270,21 @@ Compressor.prototype.compress = function(node) {
                     });
                     return maintain_this_binding(compressor, parent, compressor.self(), self.left).optimize(compressor);
                 }
-                var rr = self.right.evaluate(compressor);
+                var rr;
-                if (!rr) {
+                if (!nullish && (rr = self.right.evaluate(compressor, true)) && !(rr instanceof AST_Node)) {
-                    if (in_bool || parent.operator == "||" && parent.left === compressor.self()) {
+                    if (in_bool && !(self.right.evaluate(compressor) instanceof AST_Node)) {
-                        AST_Node.warn("Dropping side-effect-free {operator} [{file}:{line},{col}]", {
-                            operator: self.operator,
-                            file: self.start.file,
-                            line: self.start.line,
-                            col: self.start.col,
-                        });
-                        return self.left.optimize(compressor);
-                    }
-                } else if (!nullish && !(rr instanceof AST_Node)) {
-                    if (in_bool) {
                         AST_Node.warn("Boolean || always true [{file}:{line},{col}]", self.start);
-                        return make_sequence(self, [
+                        return make_sequence(self, [ self.left, make_node(AST_True, self) ]).optimize(compressor);
-                            self.left,
-                            make_node(AST_True, self)
-                        ]).optimize(compressor);
                     } else self.truthy = true;
+                } else if ((in_bool || parent.operator == "||" && parent.left === compressor.self())
+                    && !self.right.evaluate(compressor)) {
+                    AST_Node.warn("Dropping side-effect-free {operator} [{file}:{line},{col}]", {
+                        operator: self.operator,
+                        file: self.start.file,
+                        line: self.start.line,
+                        col: self.start.col,
+                    });
+                    return self.left.optimize(compressor);
                 }
                 // x && true || y ---> x ? true : y
                 if (!nullish && self.left.operator == "&&") {

test/compress/booleans.js

@@ -427,6 +427,27 @@ negated_if: {
     expect_stdout: "PASS"
 }
 
+concat_truthy: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        console.log("foo") + (console.log("bar"), "baz") || console.log("moo");
+    }
+    expect: {
+        console.log("foo") + (console.log("bar"), "baz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    expect_warnings: [
+        "WARN: + in boolean context always true [test/compress/booleans.js:1,8]",
+        "WARN: Condition left of || always true [test/compress/booleans.js:1,8]",
+    ]
+}
+
 issue_3465_1: {
     options = {
         booleans: true,

test/compress/evaluate.js

@@ -888,6 +888,25 @@ unsafe_charAt_noop: {
     expect_stdout: "f  n"
 }
 
+chained_side_effects: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log("foo") || (console.log("bar"), "baz") || console.log("moo");
+    }
+    expect: {
+        console.log("foo") || (console.log("bar"), "baz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    expect_warnings: [
+        "WARN: Condition left of || always true [test/compress/evaluate.js:1,8]",
+    ]
+}
+
 issue_1649: {
     options = {
         evaluate: true,