Function hydrateAttribute

packages/react-dom-bindings/src/client/ReactDOMComponent.js:2025–2065

(
  domElement: Element,
  propKey: string,
  attributeName: string,
  value: any,
  extraAttributes: Set<string>,
  serverDifferences: {[propName: string]: mixed},
)

}

function hydrateAttribute(
  domElement: Element,
  propKey: string,
  attributeName: string,
  value: any,
  extraAttributes: Set<string>,
  serverDifferences: {[propName: string]: mixed},
): void {
  extraAttributes.delete(attributeName);
  const serverValue = domElement.getAttribute(attributeName);
  if (serverValue === null) {
    switch (typeof value) {
      case 'undefined':
      case 'function':
      case 'symbol':
      case 'boolean':
        return;
    }
  } else {
    if (value == null) {
      // We had an attribute but shouldn't have had one, so read it
      // for the error message.
    } else {
      switch (typeof value) {
        case 'function':
        case 'symbol':
        case 'boolean':
          break;
        default: {
          if (__DEV__) {
            checkAttributeStringCoercion(value, propKey);
          }
          if (serverValue === '' + value) {
            return;
          }
        }
      }
    }
  }
  warnForPropDifference(propKey, serverValue, value, serverDifferences);
}

function hydrateBooleanAttribute(
  domElement: Element,