Fix esmorph.js:134 TypeError: code.slice(...).replace is not a function

[alfredwesterveld]

Tried to morph a file and got this error:

name = code.slice(parent.left.range[0], parent.left.range[1]).replace(/"/g, '\\"');
TypeError: code.slice(...).replace is not a function
    at /home/kaartje2go/webapplications/trace/node_modules/esmorph/lib/esmorph.js:134:87