[eslint] add eslint

.eslintrc

@@ -0,0 +1,71 @@
+{
+    "root": true,
+
+    "extends": "@ljharb/eslint-config/node/0.4",
+
+    "rules": {
+        "array-bracket-newline": 0,
+        "array-bracket-spacing": 1,
+        "array-callback-return": 1,
+        "array-element-newline": 0,
+        "brace-style": 1,
+        "camelcase": 1,
+        "comma-dangle": 1,
+        "comma-spacing": 1,
+        "complexity": 0,
+        "consistent-return": 1,
+        "curly": 1,
+        "dot-notation": 1,
+        "eqeqeq": 1,
+        "func-style": 1,
+        "function-call-argument-newline": 1,
+        "function-paren-newline": 1,
+        "global-require": 1,
+        "indent": [1, 4],
+        "key-spacing": 1,
+        "max-lines-per-function": 1,
+        "max-statements-per-line": 1,
+        "multiline-comment-style": 0,
+        "new-parens": 1,
+        "no-else-return": 1,
+        "no-extra-bind": 1,
+        "no-extra-parens": 1,
+        "no-extra-semi": 1,
+        "no-multi-assign": 1,
+        "no-new-wrappers": 1,
+        "no-param-reassign": 1,
+        "no-plusplus": 1,
+        "no-proto": 1,
+        "no-restricted-syntax": 1,
+        "no-shadow": 1,
+        "no-sparse-arrays": 1,
+        "no-trailing-spaces": 1,
+        "no-undef": 1,
+        "no-underscore-dangle": 1,
+        "no-unused-vars": 1,
+        "no-use-before-define": 1,
+        "no-useless-concat": 1,
+        "object-curly-newline": 1,
+        "one-var-declaration-per-line": 1,
+        "operator-linebreak": 1,
+        "quote-props": 1,
+        "quotes": 1,
+        "semi-style": 1,
+        "semi": 1,
+        "sort-keys": 0,
+        "space-before-function-paren": 1,
+        "space-unary-ops": 1,
+        "spaced-comment": 1,
+        "strict": 1,
+        "wrap-iife": 1,
+    },
+
+    "overrides": [
+        {
+            "files": "examples/**",
+            "rules": {
+                "no-console": 0,
+            },
+        },
+    ],
+}

package.json

@@ -8,10 +8,14 @@
         "test": "test"
     },
     "devDependencies": {
+        "@ljharb/eslint-config": "^21.0.0",
         "aud": "^2.0.1",
+        "eslint": "=8.8.0",
         "tape": "^5.6.1"
     },
     "scripts": {
+        "lint": "eslint --ext=js,mjs .",
+        "pretest": "npm run lint",
         "tests-only": "tape 'test/**/*.js'",
         "test": "npm run tests-only",
         "posttest": "aud --production"