Compile ES2015 spread to ES5
The examples are old, maybe? I guess transform-es2015-spread cannot handle the object spread operator, which is in fact handled by object-rest-spread.
README in the repo above also only includes array cases.
As @noraesae mentioned transform-es2015-spread is usually for Arrays if you would like to the same for objets you need the babel-plugin-transform-object-rest-spread plugin.