Added Linting with ESLint (#72)

* added linting, but currently the linting will fail on all files that have not been refactored.

packages/ripple-binary-codec/.eslintrc.js

@@ -0,0 +1,100 @@
+module.exports = {
+  root: true,
+
+  parser: '@typescript-eslint/parser', // Make ESLint compatible with TypeScript
+  parserOptions: {
+    // Enable linting rules with type information from our tsconfig
+    tsconfigRootDir: __dirname,
+    project: ['./tsconfig.eslint.json'],
+
+    sourceType: 'module', // Allow the use of imports / ES modules
+
+    ecmaFeatures: {
+      impliedStrict: true, // Enable global strict mode
+    },
+  },
+
+  // Specify global variables that are predefined
+  env: {
+    browser: true, // Enable browser global variables
+    node: true, // Enable node global variables & Node.js scoping
+    es2020: true, // Add all ECMAScript 2020 globals and automatically set the ecmaVersion parser option to ES2020
+    jest: true, // Add Mocha testing global variables
+  },
+
+  plugins: [
+    '@typescript-eslint', // Add some TypeScript specific rules, and disable rules covered by the typechecker
+    'import', // Add rules that help validate proper imports
+    'prettier', // Allows running prettier as an ESLint rule, and reporting differences as individual linting issues
+  ],
+
+  extends: [
+    // ESLint recommended rules
+    'eslint:recommended',
+
+    // Add TypeScript-specific rules, and disable rules covered by typechecker
+    'plugin:@typescript-eslint/eslint-recommended',
+    'plugin:@typescript-eslint/recommended',
+
+    // Add rules for import/export syntax
+    'plugin:import/errors',
+    'plugin:import/warnings',
+    'plugin:import/typescript',
+
+    // Add rules that specifically require type information using our tsconfig
+    'plugin:@typescript-eslint/recommended-requiring-type-checking',
+
+    // Enable Prettier for ESLint --fix, and disable rules that conflict with Prettier
+    'prettier/@typescript-eslint',
+    'plugin:prettier/recommended',
+  ],
+
+  // rules: {
+  //   // This rule is about explicitly using `return undefined` when a function returns any non-undefined object.
+  //   // However, since we're using TypeScript, it will yell at us if a function is not allowed to return `undefined` in its signature, so we don't need this rule.
+  //   "consistent-return": "off",
+  // },
+
+  overrides: [
+    // Overrides for all test files
+    {
+      files: 'test/**/*.ts',
+      rules: {
+        // For our Mocha test files, the pattern has been to have unnamed functions
+        'func-names': 'off',
+        // Using non-null assertions (obj!.property) cancels the benefits of the strict null-checking mode, but these are test files, so we don't care.
+        '@typescript-eslint/no-non-null-assertion': 'off',
+        // For some test files, we shadow testing constants with function parameter names
+        'no-shadow': 'off',
+        // Some of our test files declare helper classes with errors
+        'max-classes-per-file': 'off',
+      },
+    },
+    {
+      files: '**/*.ts',
+      rules: {
+        // Allow unused variables in our files when explicitly prepended with `_`.
+        '@typescript-eslint/no-unused-vars': [
+          'error',
+          { argsIgnorePattern: '^_' },
+        ],
+
+        // These rules are deprecated, but we have an old config that enables it
+        '@typescript-eslint/camelcase': 'off',
+        '@typescript-eslint/ban-ts-ignore': 'off',
+
+        // These rules are actually disabled in @xpring-eng/eslint-config-base/loose at the moment
+        '@typescript-eslint/no-unsafe-call': 'off',
+        '@typescript-eslint/no-unsafe-member-access': 'off',
+        '@typescript-eslint/no-unsafe-assignment': 'off',
+      },
+    },
+    {
+      files: ['src/XRP/default-xrp-client.ts'],
+      rules: {
+        // This is actually a good rule to have enabled, but for the XRPClient, we define a helper error message class in the same file
+        'max-classes-per-file': 'off',
+      },
+    },
+  ],
+}