Write literal braces followed by variable in heredoc

Question

        $js = <<<EOS
        var data = {$jsObjectData};
EOS;

results in var data = ~some object data~

Escaping the brace:

        $js = <<<EOS
        var data = \{$jsObjectData};
EOS;

results in var data = \{~some object data~}

I can't understand why does that backslash leak through it.

Desired output: var data = {~some object data~}

Answer 1

Just wrap it inside an extra pair of curly braces.

$js = <<<EOS
        var data = {{$jsObjectData}};
EOS;