UglifyJS/test/compress/conditionals.js

ifs_1: {
    options = {
        conditionals: true
    };
    input: {
        if (foo) bar();
        if (!foo); else bar();
        if (foo); else bar();
        if (foo); else;
    }
    expect: {
        foo&&bar();
        foo&&bar();
        foo||bar();
        foo;
    }
}

ifs_2: {
    options = {
        conditionals: true
    };
    input: {
        if (foo) {
            x();
        } else if (bar) {
            y();
        } else if (baz) {
            z();
        }

        if (foo) {
            x();
        } else if (bar) {
            y();
        } else if (baz) {
            z();
        } else {
            t();
        }
    }
    expect: {
        foo ? x() : bar ? y() : baz && z();
        foo ? x() : bar ? y() : baz ? z() : t();
    }
}

ifs_3_should_warn: {
    options = {
        conditionals : true,
        dead_code    : true,
        evaluate     : true,
        booleans     : true
    };
    input: {
        if (x && !(x + "1") && y) { // 1
            var qq;
            foo();
        } else {
            bar();
        }

        if (x || !!(x + "1") || y) { // 2
            foo();
        } else {
            var jj;
            bar();
        }
    }
    expect: {
        var qq; bar();          // 1
        var jj; foo();          // 2
    }
}

ifs_4: {
    options = {
        conditionals: true
    };
    input: {
        if (foo && bar) {
            x(foo)[10].bar.baz = something();
        } else
            x(foo)[10].bar.baz = something_else();
    }
    expect: {
        x(foo)[10].bar.baz = (foo && bar) ? something() : something_else();
    }
}

ifs_5: {
    options = {
        if_return: true,
        conditionals: true,
        comparisons: true,
    };
    input: {
        function f() {
            if (foo) return;
            bar();
            baz();
        }
        function g() {
            if (foo) return;
            if (bar) return;
            if (baz) return;
            if (baa) return;
            a();
            b();
        }
    }
    expect: {
        function f() {
            if (!foo) {
                bar();
                baz();
            }
        }
        function g() {
            if (!(foo || bar || baz || baa)) {
                a();
                b();
            }
        }
    }
}

ifs_6: {
    options = {
        conditionals: true,
        comparisons: true
    };
    input: {
        if (!foo && !bar && !baz && !boo) {
            x = 10;
        } else {
            x = 20;
        }
    }
    expect: {
        x = foo || bar || baz || boo ? 20 : 10;
    }
}

cond_1: {
    options = {
        conditionals: true
    };
    input: {
        if (some_condition()) {
            do_something(x);
        } else {
            do_something(y);
        }
    }
    expect: {
        do_something(some_condition() ? x : y);
    }
}

cond_2: {
    options = {
        conditionals: true
    };
    input: {
        if (some_condition()) {
            x = new FooBar(1);
        } else {
            x = new FooBar(2);
        }
    }
    expect: {
        x = new FooBar(some_condition() ? 1 : 2);
    }
}

cond_3: {
    options = {
        conditionals: true
    };
    input: {
        if (some_condition()) {
            new FooBar(1);
        } else {
            FooBar(2);
        }
    }
    expect: {
        some_condition() ? new FooBar(1) : FooBar(2);
    }
}

cond_4: {
    options = {
        conditionals: true
    };
    input: {
        if (some_condition()) {
            do_something();
        } else {
            do_something();
        }
    }
    expect: {
        some_condition(), do_something();
    }
}