Function coerceRef

docs/external/js/react-dom.development.js:13452–13536

(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 = {};
          }