Typescript rewrite

This originated as a new codebase, following the currently unreleased
ssz rewrite ethereum/consensus-specs#696

.babel-register

@@ -0,0 +1,15 @@
+/*
+  See
+    https://github.com/babel/babel/issues/8652
+    https://github.com/babel/babel/pull/6027
+  Babel isn't currently configured by default to read .ts files and
+  can only be configured to do so via cli or configuration below.
+
+  This file is used by mocha to interpret test files using a properly
+  configured babel.
+
+  This can (probably) be removed in babel 8.x.
+*/
+require('@babel/register')({
+  extensions: ['.ts'],
+})

.babelrc

@@ -0,0 +1,10 @@
+{
+  "presets": [
+    "@babel/env",
+    "@babel/typescript"
+  ],
+  "plugins": [
+    "@babel/proposal-class-properties",
+    "@babel/proposal-object-rest-spread"
+  ]
+}

.circleci/config.yml

@@ -76,10 +76,10 @@ jobs:
 
       - run:
           name: Check API
-          command: npm run docs && ./test-diff.sh
+          command: npm run build-docs && ./test-diff.sh
 workflows:
   version: 2
   lint_and_test:
     jobs:
       - lint
-      - test
+      - test

.eslintrc

@@ -0,0 +1,22 @@
+{
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "project": "./tsconfig.json"
+  },
+  "plugins": ["@typescript-eslint"],
+  "extends": ["plugin:@typescript-eslint/recommended"],
+  "rules": {
+    "max-line-length": {
+      "options": [180]
+    },
+    "new-parens": "error",
+    "no-caller": "error",
+    "no-bitwise": "off",
+    "@typescript-eslint/indent": ["error", 2],
+    "@typescript-eslint/no-use-before-define": "off",
+    "no-conditional-assignment": true,
+    "no-consecutive-blank-lines": false,
+    "object-literal-sort-keys": false,
+    "no-console": "warn"
+  }
+}

.gitignore

@@ -1,3 +1,5 @@
-node_modules
-.vscode
-.idea/
+.nyc_output/
+coverage/
+dist/
+lib/
+node_modules/