Any survey of a state\u27s decisional law in the labor field should include some reference to the jurisdiction of its courts over labor controversies. There would be no separate body of substantive labor law but for the intervention of Congress into employment relations affecting interstate commerce with comprehensive legislation designed to strengthen the worker in his collective capacity.\u27 The administration of this legislation by the National Labor Relations Board provides the great majority of case law governing the employment relationship. However, that residue which may be regulated exclusively or concurrently by the states is an important one, as evidenced by the number of states which have enacted their own labor relations acts
