types: export EIP1193Provider and LegacyEthereumProvider interfaces

package.json

@@ -62,13 +62,16 @@
     "superstruct": "^1.0.3"
   },
   "devDependencies": {
+    "@ethersproject/providers": "^5.7.2",
     "@lavamoat/allow-scripts": "^2.3.1",
     "@lavamoat/preinstall-always-fail": "^1.0.0",
     "@metamask/auto-changelog": "^3.1.0",
     "@metamask/eslint-config": "^12.0.0",
     "@metamask/eslint-config-jest": "^12.0.0",
     "@metamask/eslint-config-nodejs": "^12.0.0",
     "@metamask/eslint-config-typescript": "^12.0.0",
+    "@metamask/eth-query": "^3.0.1",
+    "@metamask/safe-event-emitter": "^3.0.0",
     "@types/jest": "^28.1.7",
     "@types/jest-when": "^3.5.3",
     "@types/node": "^17.0.23",

src/index.ts

@@ -8,6 +8,7 @@ export * from './collections';
 export * from './encryption-types';
 export * from './errors';
 export * from './hex';
+export * from './json-rpc-provider-types';
 export * from './json';
 export * from './keyring';
 export * from './logging';

src/json-rpc-provider-types.test-d.ts

@@ -0,0 +1,34 @@
+import { Web3Provider } from '@ethersproject/providers';
+import EthQuery from '@metamask/eth-query';
+import { expectAssignable, expectNotAssignable } from 'tsd';
+
+import type { JsonRpcRequest, LegacyEthereumProvider } from '.';
+
+// Known legacy providers
+expectAssignable<LegacyEthereumProvider>(new EthQuery({} as any));
+expectAssignable<LegacyEthereumProvider>(new Web3Provider({} as any));
+expectAssignable<LegacyEthereumProvider>({
+  send: async (method: string, params: string[]) =>
+    Promise.resolve([method, params]),
+});
+expectAssignable<LegacyEthereumProvider>({
+  // eslint-disable-next-line @typescript-eslint/no-empty-function
+  send: (_req: JsonRpcRequest, _cb: () => void) => {},
+});
+expectAssignable<LegacyEthereumProvider>({
+  send: async (req: JsonRpcRequest, _cb: (_x: null, _result: null) => void) =>
+    Promise.resolve(req),
+});
+
+expectNotAssignable<LegacyEthereumProvider>({ foo: '123' });
+expectNotAssignable<LegacyEthereumProvider>({ send: '123' });
+
+expectNotAssignable<LegacyEthereumProvider>({
+  send: (method: string, params: string[]) => [method, params],
+});
+expectNotAssignable<LegacyEthereumProvider>({
+  send: async (
+    req: JsonRpcRequest,
+    _cb: (_x: null, _result: undefined) => void,
+  ) => Promise.resolve(req),
+});

src/json-rpc-provider-types.ts

@@ -0,0 +1,92 @@
+import type SafeEventEmitter from '@metamask/safe-event-emitter';
+
+import type { JsonRpcParams, JsonRpcRequest, Json } from './json';
+import type { PartialOrAbsent } from './misc';
+
+/**
+ * An interface for the EIP-1193 specification for an Ethereum JavaScript Provider.
+ *
+ * @see [EIP-1193]{@link https://eips.ethereum.org/EIPS/eip-1193}.
+ * @see [BaseProvider]{@link https://github.com/MetaMask/providers/blob/main/src/BaseProvider.ts} in package [@metamask/providers]{@link https://www.npmjs.com/package/@metamask/providers}.
+ */
+export type EIP1193Provider = SafeEventEmitter & {
+  /**
+   * Submits an RPC request for the given method, with the given params.
+   * Resolves with the result of the method call, or rejects on error.
+   *
+   * @param args - The RPC request arguments.
+   * @param args.method - The RPC method name.
+   * @param args.params - The parameters for the RPC method.
+   * @returns A Promise that resolves with the result of the RPC method,
+   * or rejects if an error is encountered.
+   */
+  request<Params extends JsonRpcParams, Result extends Json>(
+    args: Params,
+  ): Promise<PartialOrAbsent<Result>>;
+};
+
+/**
+ * The interface for a legacy Ethereum provider.
+ *
+ * A provider of this type should be acceptable by either `eth-query`, `ethjs-query`, or Ethers' v5 `Web3Provider`.
+ */
+export type LegacyEthereumProvider =
+  | LegacyEthersProvider
+  | LegacyEthJsQueryProvider
+  | LegacyWeb3Provider;
+
+type LegacyEthersProvider = {
+  /**
+   * Send a provider request asynchronously. (ethers v5 Web3Provider)
+   *
+   * @param method - The RPC method to call.
+   * @param params - Array with method parameters.
+   * @returns A promise resolving with the result of the RPC call, or rejecting on failure.
+   */
+  send(method: string, params: any[]): Promise<Json>;
+  /*
+  send<Result extends Json = Json>(
+    method: string,
+    params: any[],
+  ): Promise<Result>;
+  */
+};
+
+type LegacyEthJsQueryProvider = {
+  /**
+   * Send a provider request asynchronously. (ethjs-query)
+   *
+   * @param req - The request to send.
+   * @param callback - A function that is called upon the success or failure of the request.
+   */
+  sendAsync<Result extends Json = Json>(
+    req: Partial<JsonRpcRequest>,
+    callback: SendAsyncCallback<Result>,
+  ): void;
+};
+
+type LegacyWeb3Provider = {
+  /**
+   * Send a provider request asynchronously.
+   *
+   * @param req - The request to send.
+   * @param callback - A function that is called upon the success or failure of the request.
+   */
+  send(req: Partial<JsonRpcRequest>, callback: SendAsyncCallback<Json>): void;
+};
+
+type SendAsyncCallback<Result extends Json> = (
+  ...args:
+    | [error: EverythingButNull, result: undefined]
+    | [error: null, result: Result]
+) => void;
+
+// What it says on the tin. We omit `null`, as that value is used for a
+// successful response to indicate a lack of an error.
+type EverythingButNull =
+  | string
+  | number
+  | boolean
+  | object
+  | symbol
+  | undefined;