code: function mergeComputeds( target, source ) {
  	const propNames = Object.keys( source );
  
  	for ( let i = 0, numNames = propNames.length; i < numNames; i++ ) {
  		const name = propNames[i];
  		const computer = source[name];
  
  		switch ( typeof computer ) {
  			case "function" :
  				break;
  
  			default :
  				throw new TypeError( `invalid definition of computed attribute named "${name}": must be a function` );
  		}
  
  		target[name] = computer;
  	}
  }
docs: Merges separately defined map of computed attributes into single schema
  matching expectations of hitchy-odem.
  
  @param {object} target resulting schema for use with hitchy-odem
  @param {object<string,function>} source maps names of computed attributes into the related computing function
  @returns {void}