script(source, {name, referrerName, address, metadata} = {}) {
    return this.internalLoader_.script(source, name, referrerName, address,
        metadata);
  }
script - Evaluate the source as a 'script'. Same as function module(),
but the source is parsed as 'script' rather than 'module'.

This function is similar to built-in eval() except that all the Loader
callbacks, eg translate() are applied before evaluation.

src may import modules, but if it directly or indirectly imports a module
that is not already loaded, a SyntaxError is thrown.

@param {string} source The source code to eval.
@param {Object} name, referrerName and address passed to normalize.
@return {Promise} fulfilled with evaluation result.