enhance join_vars (#5739)

test/benchmark.js

@@ -3,6 +3,7 @@
 
 "use strict";
 
+require("../tools/tty");
 var createHash = require("crypto").createHash;
 var fetch = require("./fetch");
 var spawn = require("child_process").spawn;

test/compress/let.js

@@ -1130,6 +1130,130 @@ default_init: {
     node_version: ">=4"
 }
 
+join_let_var_1: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        var a = "foo";
+        let b = "bar";
+        for (var c of [ a, b ])
+            console.log(c);
+    }
+    expect: {
+        "use strict";
+        let a = "foo", b = "bar";
+        for (var c of [ a, b ])
+            console.log(c);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+join_let_var_2: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        let a = "foo";
+        var b = "bar";
+        for (let c of [ a, b ])
+            console.log(c);
+    }
+    expect: {
+        "use strict";
+        let a = "foo", b = "bar";
+        for (let c of [ a, b ])
+            console.log(c);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+keep_let_var_1: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        var a = "foo";
+        let b = "bar";
+        for (var c of [ a, b ])
+            console.log(c);
+        function f() {
+            return a;
+        }
+        console.log(f(f));
+    }
+    expect: {
+        "use strict";
+        var a = "foo", c;
+        let b = "bar";
+        for (c of [ a, b ])
+            console.log(c);
+        function f() {
+            return a;
+        }
+        console.log(f(f));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "foo",
+    ]
+    node_version: ">=4"
+}
+
+keep_let_var_2: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        let a = "foo";
+        var b = "bar";
+        for (let c of [ a, b ])
+            console.log(c);
+        function f() {
+            return b;
+        }
+        console.log(f(f));
+    }
+    expect: {
+        "use strict";
+        let a = "foo";
+        var b = "bar";
+        for (let c of [ a, b ])
+            console.log(c);
+        function f() {
+            return b;
+        }
+        console.log(f(f));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
 issue_4191: {
     options = {
         functions: true,

test/release/buble.sh

@@ -41,6 +41,11 @@ rm -rf tmp/buble \
 @@ -309 +309 @@ export default class BlockStatement extends Node {
 -                               let cont = false; // TODO implement proper continue...
 +                               let cont = !declarations; // TODO implement proper continue...
+--- a/src/program/types/VariableDeclaration.js
++++ b/src/program/types/VariableDeclaration.js
+@@ -38 +38 @@ export default class VariableDeclaration extends Node {
+-                                               code.remove(c, declarator.id.start);
++                                               code.remove(c, declarator.id.start, lastDeclaratorIsPattern);
 EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
 minify_in_situ "src" \