ua

User agent detection — mobile, touch, and OS platform. All values computed once at init.

Module ua | Source packages/front/fw/src/dom/utils/ua.js | Deps none | Worker-safe no

Resolve

const ua = runtime.resolve('ua');
// Returns: { string, mobile, touch, platform }

API

ua.string() → string

Raw UA string (navigator.userAgent). Computed at init.

ua.string();
// e.g.: 'Mozilla/5.0 (iPhone; CPU iPhone OS 17_0...) AppleWebKit/605.1.15...'

ua.mobile() → boolean

Detects a mobile device via pattern matching on the UA string.

ua.mobile();  // → true on iOS, Android, etc.

Pattern-list detection (two regexes: full UA + 4-character prefix), computed once at init. Behaviour is pinned by the module's test table.

ua.touch() → boolean

Detects touch support at call time (runtime check).

ua.touch();  // → true if the device supports touch

Checks 'ontouchstart' in window AND navigator.maxTouchPoints > 0. May change on hybrid devices (touch laptops).

ua.platform() → string

Normalized OS — value computed at init.

switch (ua.platform()) {
    case 'ios':     enableIOSFeatures(); break;
    case 'android': enableAndroidFeatures(); break;
    default:        enableDesktopLayout(); break;
}

Examples

Interface adaptation

const ua = runtime.resolve('ua');
const dom = runtime.resolve('dom');

// Adapt layout based on context
if (ua.mobile()) {
    dom.attr(document.body, 'data-layout', 'mobile');
} else {
    dom.attr(document.body, 'data-layout', 'desktop');
}

// Enable touch interactions if available
if (ua.touch()) {
    enableSwipeGestures();
}

// iOS-specific feature
if (ua.platform() === 'ios') {
    // Handle notch, safe-area, navigation overlay...
    dom.style(document.body, 'padding-bottom', 'env(safe-area-inset-bottom)');
}

Notes

• mobile(), platform(), and string() return values computed once at init — no per-call overhead.
• touch() is evaluated on each call because it may change on hybrid devices.
• UA detection is heuristic and can be spoofed. Prefer feature detection (ua.touch(), media.isSupported()) when possible.
• Returns empty strings in non-browser environments.

See also

• media — multimedia capabilities (feature detection)
• events — for touch/pointer events