react-native/Libraries/Utilities/NativeDeviceInfo.js

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow strict
 * @format
 */

import type {TurboModule} from '../TurboModule/RCTExport';
import * as TurboModuleRegistry from '../TurboModule/TurboModuleRegistry';

type DisplayMetricsAndroid = {|
  width: number,
  height: number,
  scale: number,
  fontScale: number,
  densityDpi: number,
|};

export type DisplayMetrics = {|
  width: number,
  height: number,
  scale: number,
  fontScale: number,
|};

export type DimensionsPayload = {|
  window?: DisplayMetrics,
  screen?: DisplayMetrics,
  windowPhysicalPixels?: DisplayMetricsAndroid,
  screenPhysicalPixels?: DisplayMetricsAndroid,
|};

export interface Spec extends TurboModule {
  +getConstants: () => {|
    +Dimensions: DimensionsPayload,
    +isIPhoneX_deprecated?: boolean,
  |};
}

const NativeModule: Spec = TurboModuleRegistry.getEnforcing<Spec>('DeviceInfo');
let constants = null;

const NativeDeviceInfo = {
  getConstants(): {|
    +Dimensions: DimensionsPayload,
    +isIPhoneX_deprecated?: boolean,
  |} {
    if (constants == null) {
      constants = NativeModule.getConstants();
    }
    return constants;
  },
};

export default NativeDeviceInfo;