Replace Object.assign with an inline helper.
In
Object.assign(a, b);Out
var _extends = ...;
_extends(a, b);$ npm install babel-plugin-transform-object-assign.babelrc
{
"plugins": ["transform-object-assign"]
}$ babel --plugins transform-object-assign script.jsrequire("babel-core").transform("code", {
plugins: ["transform-object-assign"]
});