Function coerceRef

lib/assets/react-source/development/react.js:17012–17096

(returnFiber, current, element)

	var isArray$1 = Array.isArray;

	function coerceRef(returnFiber, current, element) {
	  var mixedRef = element.ref;

	  if (mixedRef !== null && typeof mixedRef !== 'function' && typeof mixedRef !== 'object') {
	    {
	      // TODO: Clean this up once we turn on the string ref warning for
	      // everyone, because the strict mode case will no longer be relevant
	      if ((returnFiber.mode & StrictMode || warnAboutStringRefs) && // We warn in ReactElement.js if owner and self are equal for string refs
	      // because these cannot be automatically converted to an arrow function
	      // using a codemod. Therefore, we don't have to warn about string refs again.
	      !(element._owner && element._self && element._owner.stateNode !== element._self)) {
	        var componentName = getComponentName(returnFiber.type) || 'Component';

	        if (!didWarnAboutStringRefs[componentName]) {
	          {
	            error('A string ref, "%s", has been found within a strict mode tree. ' + 'String refs are a source of potential bugs and should be avoided. ' + 'We recommend using useRef() or createRef() instead. ' + 'Learn more about using refs safely here: ' + 'https://fb.me/react-strict-mode-string-ref%s', mixedRef, getStackByFiberInDevAndProd(returnFiber));
	          }

	          didWarnAboutStringRefs[componentName] = true;
	        }
	      }
	    }

	    if (element._owner) {
	      var owner = element._owner;
	      var inst;

	      if (owner) {
	        var ownerFiber = owner;

	        if (!(ownerFiber.tag === ClassComponent)) {
	          {
	            throw Error( "Function components cannot have string refs. We recommend using useRef() instead. Learn more about using refs safely here: https://fb.me/react-strict-mode-string-ref" );
	          }
	        }

	        inst = ownerFiber.stateNode;
	      }

	      if (!inst) {
	        {
	          throw Error( "Missing owner for string ref " + mixedRef + ". This error is likely caused by a bug in React. Please file an issue." );
	        }
	      }

	      var stringRef = '' + mixedRef; // Check if previous string ref matches new string ref

	      if (current !== null && current.ref !== null && typeof current.ref === 'function' && current.ref._stringRef === stringRef) {
	        return current.ref;
	      }

	      var ref = function (value) {
	        var refs = inst.refs;

	        if (refs === emptyRefsObject) {
	          // This is a lazy pooled frozen object, so we need to initialize.
	          refs = inst.refs = {};
	        }