react/packages/react-native-renderer/src/NativeMethodsMixinUtils.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

/**
 * In the future, we should cleanup callbacks by cancelling them instead of
 * using this.
 */
export function mountSafeCallback(context: any, callback: ?Function): any {
  return function() {
    if (!callback) {
      return undefined;
    }
    if (typeof context.__isMounted === 'boolean') {
      // TODO(gaearon): this is gross and should be removed.
      // It is currently necessary because View uses createClass,
      // and so any measure() calls on View (which are done by React
      // DevTools) trigger the isMounted() deprecation warning.
      if (!context.__isMounted) {
        return undefined;
      }
      // The else branch is important so that we don't
      // trigger the deprecation warning by calling isMounted.
    } else if (typeof context.isMounted === 'function') {
      if (!context.isMounted()) {
        return undefined;
      }
    }
    return callback.apply(context, arguments);
  };
}

export function throwOnStylesProp(component: any, props: any) {
  if (props.styles !== undefined) {
    const owner = component._owner || null;
    const name = component.constructor.displayName;
    let msg =
      '`styles` is not a supported property of `' +
      name +
      '`, did ' +
      'you mean `style` (singular)?';
    if (owner && owner.constructor && owner.constructor.displayName) {
      msg +=
        '\n\nCheck the `' +
        owner.constructor.displayName +
        '` parent ' +
        ' component.';
    }
    throw new Error(msg);
  }
}

export function warnForStyleProps(props: any, validAttributes: any) {
  for (const key in validAttributes.style) {
    if (!(validAttributes[key] || props[key] === undefined)) {
      console.error(
        'You are setting the style `{ ' +
          key +
          ': ... }` as a prop. You ' +
          'should nest it in a style object. ' +
          'E.g. `{ style: { ' +
          key +
          ': ... } }`',
      );
    }
  }
}