Merge pull request #18 from Odrin/feat/provider-refactor

feat: provider refactor

package.json

@@ -1,6 +1,6 @@
 {
   "name": "everscale-inpage-provider",
-  "version": "0.3.66",
+  "version": "0.4.0",
   "description": "Web3-like interface to the Everscale blockchain",
   "repository": "https://github.com/broxus/everscale-inpage-provider",
   "main": "dist/index.js",

src/adapters.ts

@@ -0,0 +1,153 @@
+import type { Provider } from './index';
+
+declare global {
+    interface Window {
+        __ever: Provider | undefined;
+        __sparx: Provider | undefined;
+        __hasEverscaleProvider: boolean | undefined;
+    }
+}
+
+const isBrowser = typeof window !== 'undefined' && typeof window.document !== 'undefined';
+const ensurePageLoaded = !isBrowser || document.readyState === 'complete'
+    ? Promise.resolve()
+    : new Promise<void>(resolve => window.addEventListener('load', () => resolve()));
+
+/**
+ * Interface representing a provider adapter.
+ * This interface defines the methods required to interact with a provider.
+ * @category Provider
+ */
+export interface ProviderAdapter {
+    /**
+     * Retrieves the provider instance.
+     */
+    getProvider(): Promise<Provider | undefined> | Provider | undefined;
+
+    /**
+     * Checks if a provider is available.
+     */
+    hasProvider(): Promise<boolean> | boolean;
+}
+
+/**
+ * @category Provider
+ */
+export function hasEverscaleProvider(): Promise<boolean> {
+    if (!isBrowser) return Promise.resolve(false);
+    return ensurePageLoaded.then(() => window.__hasEverscaleProvider === true);
+}
+
+/**
+ * A static implementation of the `ProviderAdapter` interface that wraps a given provider instance or a promise that resolves to a provider.
+ * This adapter always indicates the presence of a provider.
+ * @category Provider
+ * @implements {ProviderAdapter}
+ */
+export class StaticProviderAdapter implements ProviderAdapter {
+    private readonly _provider: Promise<Provider> | Provider;
+
+    constructor(provider: Promise<Provider> | Provider) {
+        this._provider = provider;
+    }
+
+    public getProvider(): Promise<Provider> | Provider {
+        return this._provider;
+    }
+
+    public hasProvider(): boolean {
+        return true;
+    }
+}
+
+/**
+ * An implementation of the `ProviderAdapter` interface that wraps Ever Wallet provider.
+ * @category Provider
+ * @implements {ProviderAdapter}
+ */
+export class EverscaleProviderAdapter implements ProviderAdapter {
+    public async getProvider(): Promise<Provider | undefined> {
+        if (!(await this.hasProvider())) return;
+
+        return new Promise<Provider | undefined>((resolve) => {
+            if (window.__ever) {
+                resolve(window.__ever);
+            } else {
+                window.addEventListener(
+                    'ever#initialized',
+                    _ => resolve(window.__ever),
+                    { once: true },
+                );
+            }
+        });
+    }
+
+    public hasProvider(): Promise<boolean> {
+        return hasEverscaleProvider();
+    }
+}
+
+/**
+ * An implementation of the `ProviderAdapter` interface that wraps Sparx provider.
+ * @category Provider
+ * @implements {ProviderAdapter}
+ */
+export class SparxProviderAdapter implements ProviderAdapter {
+    public async getProvider(): Promise<Provider | undefined> {
+        if (!(await this.hasProvider())) return;
+
+        return new Promise<Provider | undefined>((resolve) => {
+            if (window.__sparx) {
+                resolve(window.__sparx);
+            } else {
+                window.addEventListener(
+                    'sparx#initialized',
+                    _ => resolve(window.__sparx),
+                    { once: true },
+                );
+            }
+        });
+    }
+
+    public hasProvider(): Promise<boolean> {
+        return hasEverscaleProvider();
+    }
+}
+
+
+/**
+ * The `FallbackProviderAdapter` class implements the `ProviderAdapter` interface
+ * and provides a mechanism to use multiple provider adapters in a fallback manner.
+ * It attempts to use the primary adapter first, and if it fails, it falls back to
+ * the subsequent adapters in the order they were provided.
+ *
+ * @category Provider
+ * @implements {ProviderAdapter}
+ */
+export class FallbackProviderAdapter implements ProviderAdapter {
+    private readonly _adapters: [ProviderAdapter, ...ProviderAdapter[]];
+
+    constructor(adapter: ProviderAdapter, ...fallbacks: ProviderAdapter[]) {
+        this._adapters = [adapter, ...fallbacks];
+    }
+
+    public async getProvider(): Promise<Provider | undefined> {
+        for (const adapter of this._adapters) {
+            const provider = await adapter.getProvider();
+            if (provider) return provider;
+        }
+
+        return undefined;
+    }
+
+    public async hasProvider(): Promise<boolean> {
+        for (const adapter of this._adapters) {
+            if (await adapter.hasProvider()) return true;
+        }
+        return false;
+    }
+}
+
+export function isProviderAdapter(value: any): value is ProviderAdapter {
+    return !!value && 'getProvider' in value && 'hasProvider' in value;
+}