Using ejs (node flavour), how to default a value if missing

example.ejs

<!-- prints "no email given" if no email passed in to locals, otherwise shows val -->
<%=: locals | get:"email","no email given" %>

gistfile2.js

// where ejs is the ejs required module

// overwrite the 'get' filter
ejs.filters.get = function(obj, prop, def) {
  return obj[prop] === undefined ? def : obj[prop];
};

// for usage see example.ejs