[eslint config] [breaking] disallow unneeded ternary expressions.

Author: ljharb

README.md

@@ -1295,24 +1295,40 @@ Other Style Guides
     eslint rules: [`no-nested-ternary`](http://eslint.org/docs/rules/no-nested-ternary.html).
 
     ```javascript
-    //bad
+    // bad
     const foo = maybe1 > maybe2
       ? "bar"
       : value1 > value2 ? "baz" : null;
 
-    //better
+    // better
     const maybeNull = value1 > value2 ? 'baz' : null;
 
     const foo = maybe1 > maybe2
       ? 'bar'
       : maybeNull;
 
-    //best
+    // best
     const maybeNull = value1 > value2 ? 'baz' : null;
 
     const foo = maybe1 > maybe2 ? 'bar' : maybeNull;
     ```
 
+  - [15.6](#15.6) <a name='15.6'></a> Avoid unneeded ternary statements.
+
+    eslint rules: [`no-unneeded-ternary`](http://eslint.org/docs/rules/no-unneeded-ternary.html).
+
+    ```javascript
+    // bad
+    const foo = a ? a : b;
+    const bar = c ? true : false;
+    const baz = c ? false : true;
+
+    // good
+    const foo = a || b;
+    const bar = !!c;
+    const baz = !c;
+    ```
+
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packages/eslint-config-airbnb/rules/style.js

@@ -74,7 +74,9 @@ module.exports = {
     // disallow dangling underscores in identifiers
     'no-underscore-dangle': 0,
     // disallow the use of Boolean literals in conditional expressions
-    'no-unneeded-ternary': 0,
+    // also, prefer `a || b` over `a ? a : b`
+    // http://eslint.org/docs/rules/no-unneeded-ternary
+    'no-unneeded-ternary': [2, { "defaultAssignment": false }],
     // require padding inside curly braces
     'object-curly-spacing': [2, 'always'],
     // allow just one var statement per function