Add slippage service - suggest 3 layered architecture

apps/api/src/app/routes/chains/__chainId/markets/__sellToken-__buyToken/slippageTolerance.ts

@@ -4,6 +4,10 @@ import {
 } from '../../../../../schemas';
 import { FastifyPluginAsync } from 'fastify';
 import { FromSchema, JSONSchema } from 'json-schema-to-ts';
+import { getSlippageService } from '@cowprotocol/services';
+
+// TODO:  Add this in a follow up PR
+// import { ALL_SUPPORTED_CHAIN_IDS } from '@cowprotocol/cow-sdk';
 
 interface Result {
   slippageBps: number;
@@ -38,7 +42,7 @@ const responseSchema = {
       description:
         'Slippage tolerance in basis points. One basis point is equivalent to 0.01% (1/100th of a percent)',
       type: 'number',
-      examples: [50, 100, 200],
+      examples: [50, 100, 200], // [ALL_SUPPORTED_CHAIN_IDS],
       minimum: 0,
       maximum: 10000,
     },
@@ -47,6 +51,8 @@ const responseSchema = {
 
 type RouteSchema = FromSchema<typeof routeSchema>;
 
+const slippageService = getSlippageService();
+
 const root: FastifyPluginAsync = async (fastify): Promise<void> => {
   // example: http://localhost:3010/chains/1/markets/0x6b175474e89094c44da98b954eedeac495271d0f-0x2260fac5e5542a773aa44fbcfedf7c193bc2c599/slippageTolerance
   fastify.get<{
@@ -67,7 +73,11 @@ const root: FastifyPluginAsync = async (fastify): Promise<void> => {
       fastify.log.info(
         `Get default slippage for market ${baseTokenAddress}-${quoteTokenAddress} on chain ${chainId}`
       );
-      reply.send({ slippageBps: 50 });
+      const slippageBps = slippageService.getSlippageBps(
+        baseTokenAddress,
+        quoteTokenAddress
+      );
+      reply.send({ slippageBps });
     }
   );
 };

libs/repositories/.eslintrc.json

@@ -0,0 +1,18 @@
+{
+  "extends": ["../../.eslintrc.json"],
+  "ignorePatterns": ["!**/*"],
+  "overrides": [
+    {
+      "files": ["*.ts", "*.tsx", "*.js", "*.jsx"],
+      "rules": {}
+    },
+    {
+      "files": ["*.ts", "*.tsx"],
+      "rules": {}
+    },
+    {
+      "files": ["*.js", "*.jsx"],
+      "rules": {}
+    }
+  ]
+}

libs/repositories/README.md

@@ -0,0 +1,7 @@
+# repositories
+
+This library was generated with [Nx](https://nx.dev).
+
+## Running unit tests
+
+Run `nx test repositories` to execute the unit tests via [Jest](https://jestjs.io).

libs/repositories/jest.config.ts

@@ -0,0 +1,11 @@
+/* eslint-disable */
+export default {
+  displayName: 'repositories',
+  preset: '../../jest.preset.js',
+  testEnvironment: 'node',
+  transform: {
+    '^.+\\.[tj]s$': ['ts-jest', { tsconfig: '<rootDir>/tsconfig.spec.json' }],
+  },
+  moduleFileExtensions: ['ts', 'js', 'html'],
+  coverageDirectory: '../../coverage/libs/repositories',
+};

libs/repositories/project.json

@@ -0,0 +1,30 @@
+{
+  "name": "repositories",
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "sourceRoot": "libs/repositories/src",
+  "projectType": "library",
+  "targets": {
+    "lint": {
+      "executor": "@nx/linter:eslint",
+      "outputs": ["{options.outputFile}"],
+      "options": {
+        "lintFilePatterns": ["libs/repositories/**/*.ts"]
+      }
+    },
+    "test": {
+      "executor": "@nx/jest:jest",
+      "outputs": ["{workspaceRoot}/coverage/{projectRoot}"],
+      "options": {
+        "jestConfig": "libs/repositories/jest.config.ts",
+        "passWithNoTests": true
+      },
+      "configurations": {
+        "ci": {
+          "ci": true,
+          "codeCoverage": true
+        }
+      }
+    }
+  },
+  "tags": []
+}

libs/repositories/src/UsdRepository.ts

@@ -0,0 +1,16 @@
+import { get } from 'http';
+
+export interface UsdRepository {
+  getDailyUsdPrice(tokenAddress: string, date: Date): Promise<number>;
+}
+
+export class UsdRepositoryMock implements UsdRepository {
+  async getDailyUsdPrice(tokenAddress: string, date: Date): Promise<number> {
+    return 1234;
+  }
+}
+
+// TODO: Remove once we have IoC
+export function getUsdRepository(): UsdRepository {
+  return new UsdRepositoryMock();
+}

libs/repositories/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "module": "commonjs"
+  },
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.lib.json"
+    },
+    {
+      "path": "./tsconfig.spec.json"
+    }
+  ]
+}

libs/repositories/tsconfig.lib.json

@@ -0,0 +1,11 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "commonjs",
+    "outDir": "../../dist/out-tsc",
+    "declaration": true,
+    "types": ["node"]
+  },
+  "exclude": ["jest.config.ts", "src/**/*.spec.ts", "src/**/*.test.ts"],
+  "include": ["src/**/*.ts"]
+}

libs/repositories/tsconfig.spec.json

@@ -0,0 +1,14 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "module": "commonjs",
+    "types": ["jest", "node"]
+  },
+  "include": [
+    "jest.config.ts",
+    "src/**/*.test.ts",
+    "src/**/*.spec.ts",
+    "src/**/*.d.ts"
+  ]
+}

libs/services/.eslintrc.json

@@ -0,0 +1,18 @@
+{
+  "extends": ["../../.eslintrc.json"],
+  "ignorePatterns": ["!**/*"],
+  "overrides": [
+    {
+      "files": ["*.ts", "*.tsx", "*.js", "*.jsx"],
+      "rules": {}
+    },
+    {
+      "files": ["*.ts", "*.tsx"],
+      "rules": {}
+    },
+    {
+      "files": ["*.js", "*.jsx"],
+      "rules": {}
+    }
+  ]
+}

libs/services/README.md

@@ -0,0 +1,7 @@
+# services
+
+This library was generated with [Nx](https://nx.dev).
+
+## Running unit tests
+
+Run `nx test services` to execute the unit tests via [Jest](https://jestjs.io).

libs/services/jest.config.ts

@@ -0,0 +1,11 @@
+/* eslint-disable */
+export default {
+  displayName: 'services',
+  preset: '../../jest.preset.js',
+  testEnvironment: 'node',
+  transform: {
+    '^.+\\.[tj]s$': ['ts-jest', { tsconfig: '<rootDir>/tsconfig.spec.json' }],
+  },
+  moduleFileExtensions: ['ts', 'js', 'html'],
+  coverageDirectory: '../../coverage/libs/services',
+};

libs/services/project.json

@@ -0,0 +1,30 @@
+{
+  "name": "services",
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "sourceRoot": "libs/services/src",
+  "projectType": "library",
+  "targets": {
+    "lint": {
+      "executor": "@nx/linter:eslint",
+      "outputs": ["{options.outputFile}"],
+      "options": {
+        "lintFilePatterns": ["libs/services/**/*.ts"]
+      }
+    },
+    "test": {
+      "executor": "@nx/jest:jest",
+      "outputs": ["{workspaceRoot}/coverage/{projectRoot}"],
+      "options": {
+        "jestConfig": "libs/services/jest.config.ts",
+        "passWithNoTests": true
+      },
+      "configurations": {
+        "ci": {
+          "ci": true,
+          "codeCoverage": true
+        }
+      }
+    }
+  },
+  "tags": []
+}

libs/services/src/SlippageService/SlippageService.spec.ts

@@ -0,0 +1,9 @@
+import { getSlippageService } from './SlippageService';
+
+const slippageService = getSlippageService();
+
+describe('SlippageService', () => {
+  it('should return always 50', () => {
+    expect(slippageService.getSlippageBps('0x0', '0x0')).toEqual(50);
+  });
+});

libs/services/src/SlippageService/SlippageService.ts

@@ -0,0 +1,20 @@
+/**
+ * BPS (Basis Points)
+ */
+export type Bps = number;
+
+export interface SlippageService {
+  getSlippageBps(quoteTokenAddress: string, baseTokenAddress: string): Bps;
+}
+
+// TODO: Find good name for the implementation, as Leandro don't like "Impl" suffix, just don't want to couple it to add Coingecko in its name (as that would couple it to the data-source, and the adding a name to specify the algorithm might complicate the name, as this will use some custom logic based on standard deviation, so for now as we plan to have just one implementation, I want to keep it simple. But happy to get ideas here)
+export class SlippageServiceImpl implements SlippageService {
+  getSlippageBps(_quoteTokenAddress: string, _baseTokenAddress: string): Bps {
+    return 50;
+  }
+}
+
+// TODO: This is just temporal! I will introduce a IoC framework in a follow up
+export function getSlippageService(): SlippageService {
+  return new SlippageServiceImpl();
+}

libs/services/src/index.ts

@@ -0,0 +1 @@
+export * from './SlippageService/SlippageService';

libs/services/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "module": "commonjs"
+  },
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.lib.json"
+    },
+    {
+      "path": "./tsconfig.spec.json"
+    }
+  ]
+}

libs/services/tsconfig.lib.json

@@ -0,0 +1,11 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "commonjs",
+    "outDir": "../../dist/out-tsc",
+    "declaration": true,
+    "types": ["node"]
+  },
+  "exclude": ["jest.config.ts", "src/**/*.spec.ts", "src/**/*.test.ts"],
+  "include": ["src/**/*.ts"]
+}

libs/services/tsconfig.spec.json

@@ -0,0 +1,14 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "module": "commonjs",
+    "types": ["jest", "node"]
+  },
+  "include": [
+    "jest.config.ts",
+    "src/**/*.test.ts",
+    "src/**/*.spec.ts",
+    "src/**/*.d.ts"
+  ]
+}

tsconfig.base.json

@@ -10,30 +10,20 @@
     "importHelpers": true,
     "target": "es2015",
     "module": "esnext",
-    "lib": [
-      "es2020",
-      "dom"
-    ],
+    "lib": ["es2020", "dom"],
     "skipLibCheck": true,
     "skipDefaultLibCheck": true,
     "baseUrl": ".",
     "resolveJsonModule": true,
     "esModuleInterop": true,
     "allowJs": true,
     "paths": {
-      "@cowprotocol/abis": [
-        "libs/abis/src/index.ts"
-      ],
-      "@cowprotocol/cms-api": [
-        "libs/cms-api/src/index.ts"
-      ],
-      "@cowprotocol/notifications": [
-        "libs/notifications/src/index.ts"
-      ]
+      "@cowprotocol/abis": ["libs/abis/src/index.ts"],
+      "@cowprotocol/cms-api": ["libs/cms-api/src/index.ts"],
+      "@cowprotocol/notifications": ["libs/notifications/src/index.ts"],
+      "@cowprotocol/repositories": ["libs/repositories/src/index.ts"],
+      "@cowprotocol/services": ["libs/services/src/index.ts"]
     }
   },
-  "exclude": [
-    "node_modules",
-    "tmp"
-  ]
-}
+  "exclude": ["node_modules", "tmp"]
+}

yarn.lock

@@ -6602,7 +6602,7 @@ node-fetch@^2.6.12:
 
 node-fetch@^3.3.2:
   version "3.3.2"
-  resolved "https://registry.npmjs.org/node-fetch/-/node-fetch-3.3.2.tgz"
+  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-3.3.2.tgz#d1e889bacdf733b4ff3b2b243eb7a12866a0b78b"
   integrity sha512-dRB78srN/l6gqWulah9SrxeYnxeddIG30+GOqK/9OlLVyLg3HPnr6SqOWTWOXKRwC2eGYCkZ59NNuSgvSrpgOA==
   dependencies:
     data-uri-to-buffer "^4.0.0"