#4 make "node-babel-helper-is-void-0" an optional dependency

return (
  t.isUnaryExpression(expr, { operator: "void" }) &&
  t.isNumericLiteral(expr.argument, { value: 0 })
);

Seriously it's module.exports = function(t) { return function isVoid0(expr) { return ( t.isUnaryExpression(expr, { operator: "void" }) && t.isNumericLiteral(expr.argument, { value: 0 }) ); }; }; you don't need a whole bunch of dependency overhead for that bullshit.