override.js
function isPackage(pkg) {
  return pkg.name && pkg.version && (pkg.dependencies || pkg.devDependencies)
}
function isPackage(pkg) {
  return pkg.name && pkg.version && (pkg.dependencies || pkg.devDependencies)
}
/*

if opts.override is non null, then resolve modules that match from there.

{
either pass in the package.json you want for that package.
foo: foo_package_json

or pass in another valid range...
bar: {verison: '1.0.1', to: '~2.0.0'}
this will replace any bar that can use 1.0.1 with something that matches ~2.0.0
}