dead_code_1: { options = { dead_code: true }; input: { function f() { a(); b(); x = 10; return; if (x) { y(); } } } expect: { function f() { a(); b(); x = 10; return; } } } dead_code_2_should_warn: { options = { dead_code: true }; input: { function f() { g(); x = 10; throw "foo"; // completely discarding the `if` would introduce some // bugs. UglifyJS v1 doesn't deal with this issue; in v2 // we copy any declarations to the upper scope. if (x) { y(); var x; function g(){}; // but nested declarations should not be kept. (function(){ var q; function y(){}; })(); } } } expect: { function f() { g(); x = 10; throw "foo"; var x; function g(){}; } } } dead_code_constant_boolean_should_warn_more: { options = { dead_code : true, loops : true, booleans : true, conditionals : true, evaluate : true }; input: { while (!((foo && bar) || (x + "0"))) { console.log("unreachable"); var foo; function bar() {} } for (var x = 10; x && (y || x) && (!typeof x); ++x) { asdf(); foo(); var moo; } } expect: { var foo; function bar() {} // nothing for the while // as for the for, it should keep: var x = 10; var moo; } }