in rfcs/20210731-tfjs-named-tensors/gtensor.ts [260:266]
export function stack<G extends DName, NewD extends DName>(
newDimName: NewD,
stackDims: Dims<G>[],
): Dims<G|NewD> {
const gtensors = stackDims.map(gtensorOfDims);
return stackGtensors(newDimName, gtensors).dim;
}