Direction

import { Component, inject } from '@angular/core';
import { Direction } from '@ng-native/device';

@Component({
  selector: 'app-drawer',
  template: `<view [style.left]="direction.rtl() ? null : 0" />`,
})
export class Drawer {
  protected readonly direction = inject(Direction);
}

The cascade already mirrors the paint for direction: rtl without anything being injected - padding, text alignment and box order all flip on their own, and Yoga inherits that down the shadow tree without anyone asking. Direction is for the TypeScript that computes a position outside of CSS: resolving an align: start against a concrete edge, mapping a drag's x-delta onto a value, naming which edge a panel opens from. current is 'ltr' or 'rtl'; rtl is the same fact as a boolean, because most callers branch on it rather than switch.

A direction set in a stylesheet or an inline style also applies to a subtree, as on the web: the row reverses, logical edges swap, and a paragraph inside starts at the subtree's start edge whatever its script, with its base writing direction following. text-align: start and end resolve against that direction, left and right stay on the side they name, and an explicit writingDirection on a text is kept. A paragraph with no direction anywhere above it keeps the platform's natural alignment, which follows the app's language.

An app can override Direction for a subtree with its own directive, providing a DirectionContext in its place, exactly as Angular's CDK provides Dir in place of Directionality. Everything that injects Direction gets whichever of the two is closest without needing to know which one it got.

Off a device and on the web

Off a device and on startup, current reads I18nManager.isRTL once and never changes: React Native settles direction from the device's own locale while the native side starts up, and I18nManager.forceRTL only takes effect after a restart, so isRTL cannot change under a running app - which is why there is nothing to subscribe to on native. The browser source is the exception: document.dir is a mutable attribute, so a consumer should not have to know which platform it is on to read the signal.

Reference