feat: context class

package.json

@@ -19,6 +19,7 @@
     "@commitlint/config-conventional": "^7.6.0",
     "@semantic-release/git": "^8.0.0",
     "@types/jest": "^23.3.10",
+    "@types/json-stable-stringify": "^1.0.32",
     "@types/node": "^13.1.8",
     "@typescript-eslint/eslint-plugin": "^2.17.0",
     "@typescript-eslint/parser": "^2.17.0",
@@ -52,5 +53,10 @@
   },
   "publishConfig": {
     "access": "public"
+  },
+  "dependencies": {
+    "@polymathnetwork/polkadot": "^0.101.0-beta.8",
+    "bn.js": "^5.1.1",
+    "json-stable-stringify": "^1.0.1"
   }
 }

src/Context.ts

@@ -0,0 +1,81 @@
+import { Identity } from './api/entities/Identity';
+import { ApiPromise, Keyring } from '@polymathnetwork/polkadot/api';
+import { KeyringPair, KeyringPair$Meta } from '@polkadot/keyring/types';
+import stringToU8a from '@polkadot/util/string/toU8a';
+import { LinkedKeyInfo } from '@polymathnetwork/polkadot/types/interfaces';
+import { Option } from '@polymathnetwork/polkadot/types/codec';
+
+interface BuildParams {
+  polymeshApi: ApiPromise;
+  seed: string | undefined;
+}
+
+interface ConstructorParams {
+  polymeshApi: ApiPromise;
+  currentPair?: KeyringPair;
+  did?: Option<LinkedKeyInfo>;
+}
+
+interface AddressPair {
+  address: string;
+  meta: KeyringPair$Meta;
+}
+
+/**
+ * Context in which the SDK is being used
+ *
+ * - Holds the current low level API
+ * - Holds the current keyring pair
+ * - Holds the current Identity
+ */
+export class Context {
+  private static keyring: Keyring = new Keyring({ type: 'sr25519' });
+
+  public polymeshApi: ApiPromise;
+
+  public currentPair: KeyringPair | undefined;
+
+  public currentIdentity: Identity | undefined;
+
+  private constructor(params: ConstructorParams) {
+    const { polymeshApi, currentPair, did } = params;
+
+    this.polymeshApi = polymeshApi;
+
+    if (currentPair && did) {
+      this.currentPair = currentPair;
+      this.currentIdentity = new Identity({ did: did.toString() }, this);
+    }
+  }
+
+  static async create(params: BuildParams) {
+    const { polymeshApi, seed } = params;
+
+    if (seed) {
+      if (seed.length != 32) {
+        throw new Error('Seed must be 32 length size');
+      }
+
+      const currentPair = Context.keyring.addFromSeed(stringToU8a(seed));
+      const did = await polymeshApi.query.identity.keyToIdentityIds(currentPair.publicKey);
+      return new Context({ polymeshApi, currentPair, did });
+    }
+    return new Context({ polymeshApi });
+  }
+
+  public getAddresses = (): Array<AddressPair> => {
+    const { keyring } = Context;
+    return keyring.getPairs().map(({ address, meta }) => {
+      return { address, meta };
+    });
+  };
+
+  public setPair = (address: string) => {
+    const { keyring } = Context;
+    try {
+      this.currentPair = keyring.getPair(address);
+    } catch ({}) {
+      throw new Error('The address is not present in the keyring set');
+    }
+  };
+}

src/api/entities/Identity.ts

@@ -13,7 +13,7 @@ export interface UniqueIdentifiers {
 /**
  * Constructor parameters
  */
-export type Params = UniqueIdentifiers
+export type Params = UniqueIdentifiers;
 
 function isUniqueIdentifiers(identifier: any): identifier is UniqueIdentifiers {
   const { did } = identifier;
@@ -80,6 +80,6 @@ export class Identity extends Entity {
    */
   public getPolyBalance = async (): Promise<Balance> => {
     const { context, did } = this;
-    return context.api.query.balances.identityBalance(did);
+    return context.polymeshApi.query.balances.identityBalance(did);
   };
 }