@su-labs/font-size/index.d.ts

A lightweight Angular service for dynamic font size management.

import * as _angular_core from '@angular/core';

interface FontSizeConfig {
    defaultSize: number;
    minSize: number;
    maxSize: number;
    step: number;
    storageKey?: string;
    cssVarName?: string;
}

declare class FontSizeService {
    /**
     * Default font size in pixels.
     * Can be overridden via {@link configure}.
     */
    defaultSize: _angular_core.WritableSignal<number>;
    /**
     * Minimum allowed font size in pixels.
     * Can be overridden via {@link configure}.
     */
    minSize: _angular_core.WritableSignal<number>;
    /**
     * Maximum allowed font size in pixels.
     * Can be overridden via {@link configure}.
     */
    maxSize: _angular_core.WritableSignal<number>;
    /**
     * Default step value (in pixels) for increase/decrease operations.
     * Can be overridden via {@link configure} or per call in {@link increase} / {@link decrease}.
     */
    step: _angular_core.WritableSignal<number>;
    /**
     * Key used for persisting the font size in localStorage.
     * Defaults to `"app:font-size"`.
     */
    private storageKey;
    /**
     * CSS custom property name where the font size is applied.
     * Defaults to `"--base-font-size"`.
     */
    private cssVarName;
    /**
     * Current font size state (reactive).
     */
    fontSize: _angular_core.WritableSignal<number>;
    /**
     * True if current font size equals the default size.
     */
    isDefault: _angular_core.Signal<boolean>;
    /**
     * True if current font size equals the maximum size.
     */
    isMax: _angular_core.Signal<boolean>;
    /**
     * True if current font size equals the minimum size.
     */
    isMin: _angular_core.Signal<boolean>;
    /**
     * Updates the configuration for font size handling.
     * Any omitted values will fall back to their defaults.
     *
     * @param cfg Partial configuration object (min, max, default, step, storage key, CSS variable name).
     */
    configure(cfg?: Partial<FontSizeConfig>): void;
    /**
     * Initializes the font size service.
     * Loads the persisted value (if available), clamps it,
     * applies it to the DOM, and updates internal state.
     * Should typically be called once at application startup.
     */
    init(): void;
    /**
     * Sets the font size to a specific value (clamped within min/max).
     *
     * @param size Desired font size in pixels.
     */
    setFontSize(size: number): void;
    /**
     * Increases the font size.
     *
     * @param step Optional custom step (pixels). Falls back to configured {@link step} if omitted.
     */
    increase(step?: number): void;
    /**
     * Decreases the font size.
     *
     * @param step Optional custom step (pixels). Falls back to configured {@link step} if omitted.
     */
    decrease(step?: number): void;
    /**
     * Resets the font size to the configured {@link defaultSize}.
     * Also removes the persisted value from localStorage.
     */
    reset(): void;
    /**
     * Clamps a given value between the configured {@link minSize} and {@link maxSize}.
     *
     * @param size Value to clamp.
     * @returns Clamped value within the allowed range.
     */
    private clamp;
    /**
     * Reads the font size from localStorage.
     * Falls back to {@link defaultSize} if no value is stored or value is invalid.
     *
     * @returns Stored font size or default.
     */
    private readFromStorage;
    /**
     * Persists the current font size in localStorage.
     *
     * @param size Font size value to persist.
     */
    private writeToStorage;
    /**
     * Applies the current font size to the DOM
     * using the configured CSS custom property name.
     *
     * @param size Font size value in pixels.
     */
    private applyCssVar;
    static ɵfac: _angular_core.ɵɵFactoryDeclaration<FontSizeService, never>;
    static ɵprov: _angular_core.ɵɵInjectableDeclaration<FontSizeService>;
}

export { FontSizeService };
export type { FontSizeConfig };