Normalize rule config values (#169)

The rule validation script wasn't taking into account that extended configs can use numerical (`0, 1, 2`) or text (`off, warn, error`) notation for rule configs. This PR normalizes all rules in the snapshot to use text notation.

I had to parameterize this behavior to make an exception for when we compute the required Prettier rules, because Prettier intentionally uses numerical notation for a subset of its rules to distinguish them from the rest.

Applying this change caught some redundantly configured rules.

packages/base/rules-snapshot.json

@@ -9,7 +9,7 @@
   "@typescript-eslint/no-extra-parens": "off",
   "@typescript-eslint/no-extra-semi": "off",
   "@typescript-eslint/object-curly-spacing": "off",
-  "@typescript-eslint/quotes": 0,
+  "@typescript-eslint/quotes": "off",
   "@typescript-eslint/semi": "off",
   "@typescript-eslint/space-before-function-paren": "off",
   "@typescript-eslint/space-infix-ops": "off",
@@ -23,7 +23,7 @@
   "arrow-parens": "off",
   "arrow-spacing": "off",
   "babel/object-curly-spacing": "off",
-  "babel/quotes": 0,
+  "babel/quotes": "off",
   "babel/semi": "off",
   "block-scoped-var": "error",
   "block-spacing": "off",
@@ -128,7 +128,7 @@
   "key-spacing": "off",
   "keyword-spacing": "off",
   "linebreak-style": "off",
-  "lines-around-comment": 0,
+  "lines-around-comment": "off",
   "lines-between-class-members": "error",
   "max-len": "off",
   "max-statements-per-line": [
@@ -473,11 +473,11 @@
   "vue/html-end-tags": "off",
   "vue/html-indent": "off",
   "vue/html-quotes": "off",
-  "vue/html-self-closing": 0,
+  "vue/html-self-closing": "off",
   "vue/key-spacing": "off",
   "vue/keyword-spacing": "off",
   "vue/max-attributes-per-line": "off",
-  "vue/max-len": 0,
+  "vue/max-len": "off",
   "vue/multiline-html-element-content-newline": "off",
   "vue/mustache-interpolation-spacing": "off",
   "vue/no-extra-parens": "off",

packages/base/src/index.js

@@ -29,27 +29,8 @@ module.exports = {
       },
     ],
 
-    // Prettier has some opinions on mixed-operators, and there is ongoing work
-    // to make the output code clear. The workaround for keeping this rule enabled
-    // requires breaking parts of operations into different variables -- which we
-    // decided to be worse.
-    // https://github.com/prettier/eslint-config-prettier#no-mixed-operators
-    'no-mixed-operators': 'off',
-
-    // Prettier wraps e.g. single line functions with ternaries in parens by default, but
-    // if the line is long enough it breaks it into a separate line and removes the parens.
-    // The second behavior conflicts with this rule. There is some advice on the repo about
-    // how you can keep it enabled:
-    // https://github.com/prettier/eslint-config-prettier#no-confusing-arrow
-    // However, in practice this conflicts with prettier adding parens around short lines,
-    // when autofixing in vscode and others.
-    'no-confusing-arrow': 'off',
-
     'curly': ['error', 'all'],
-    'max-len': 'off',
     'no-tabs': 'error',
-    'no-unexpected-multiline': 'off',
-    'quotes': 'off',
 
     // Not required by prettier, but potentially gotchas.
     'no-restricted-syntax': ['error', 'SequenceExpression'],

scripts/validate-configs.js

@@ -360,18 +360,17 @@ function getFlatConfigWithBaseConfig(configObject) {
  * disabled when using Prettier.
  */
 function getRequiredPrettierRules() {
-  return Object.entries(getFlatRules(getFlatConfig(prettierConfig))).reduce(
-    (allRules, [ruleName, ruleValue]) => {
-      // Rules set to 'off' should never be enabled.
-      // Rules set to 0 (number) may sometimes be included. We don't attend to those.
-      // https://github.com/Prettier/eslint-config-Prettier/blob/abf3ba1/index.js#L7-L9
-      if (ruleValue === OFF) {
-        allRules.push(ruleName);
-      }
-      return allRules;
-    },
-    [],
-  );
+  return Object.entries(
+    getFlatRules(getFlatConfig(prettierConfig), false),
+  ).reduce((allRules, [ruleName, ruleValue]) => {
+    // Rules set to 'off' should never be enabled.
+    // Rules set to 0 (number) may sometimes be included. We don't attend to those.
+    // https://github.com/Prettier/eslint-config-Prettier/blob/abf3ba1/index.js#L7-L9
+    if (ruleValue === OFF) {
+      allRules.push(ruleName);
+    }
+    return allRules;
+  }, []);
 }
 
 //----------------
@@ -383,10 +382,13 @@ function getRequiredPrettierRules() {
  * of its extended configs (if any) in a single, flat object.
  *
  * @param {Record<string, unknown>[]} flatConfig - A flat eslint config array.
+ * @param {boolean} [normalizeRules] - Whether to normalize rule config values
+ * to use string notation (off, warn, error) instead of numerical notation
+ * (0, 1, 2). Non-numerical values are passed through.
  * @returns {Record<string, unknown>} An object of eslint rule names and their
  * configuration.
  */
-function getFlatRules(flatConfig) {
+function getFlatRules(flatConfig, normalizeRules = true) {
   // Flatten the config array into a single object
   const rawFlatRules = flatConfig.reduce((flatRules, config) => {
     if (RULES in config) {
@@ -399,25 +401,55 @@ function getFlatRules(flatConfig) {
   }, {});
 
   // Sort the flat rules alphabetically and return them
-  return sortObject(rawFlatRules);
+  return normalizeRules
+    ? normalizeObject(rawFlatRules, normalizeRuleConfigValue)
+    : normalizeObject(rawFlatRules);
 }
 
 /**
  * Sorts the keys of the given object, inserts them in that order in a new
- * object, and returns that object.
+ * object, and returns that object. Optionally normalizes the values of the
+ * object during sorting.
  *
  * @param {Record<string, unknown>} obj - The object to sort.
+ * @param {Function} [valueNormalizer] - A function that takes a value and
+ * returns a "normalized" version of it. The value of every key on the sorted
+ * object will be passed through this function, if present.
  * @returns {Record<string, unknown>} The sorted object.
  */
-function sortObject(obj) {
+function normalizeObject(obj, valueNormalizer) {
   return Object.keys(obj)
     .sort()
     .reduce((sortedObj, key) => {
-      sortedObj[key] = obj[key];
+      sortedObj[key] = valueNormalizer ? valueNormalizer(obj[key]) : obj[key];
       return sortedObj;
     }, {});
 }
 
+/**
+ * Given an ESLint rule config value, converts it from numerical (0, 1, 2) to
+ * string (off, warn, error) notation, or just returns the given value.
+ *
+ * @param {unknown} configValue - The rule config value to normalize.
+ * @returns {string | typeof configValue} The normalized rule config value.
+ */
+function normalizeRuleConfigValue(configValue) {
+  if (typeof configValue !== 'number' && typeof configValue !== 'string') {
+    return configValue;
+  }
+
+  switch (String(configValue)) {
+    case '0':
+      return 'off';
+    case '1':
+      return 'warn';
+    case '2':
+      return 'error';
+    default:
+      return configValue;
+  }
+}
+
 /**
  * Takes an eslint config object and flattens it and the configs it
  * extends into a single array, ordered by their dependency relationships.
@@ -520,7 +552,7 @@ function logSnapshotViolations(snapshotViolations) {
   console.error(
     `\nError: Computed snapshot differs from the existing snapshot for the following package(s). Take a new snapshot and try again.\n\n${tabs(
       1,
-    )}${snapshotViolations.join(`\n${tabs(1)}`)}`,
+    )}${snapshotViolations.join(`\n${tabs(1)}`)}\n`,
   );
 }