[guide] [eslint config] [base] [breaking] Simplifies `no-mixed-operat…

…ors`

- adds warning on mixing `/` and `*` arithmetic operators
- removes warnings on mixing `**` and arithmetic operators
- removes warning on mixing `in` and `instanceof`
- removes warning on mixing `~` with other bitwise operators
- removes mixing of assignment operators with comparison operators

README.md

@@ -2043,7 +2043,8 @@ Other Style Guides
     ```
 
   <a name="comparison--no-mixed-operators"></a>
-  - [15.8](#comparison--no-mixed-operators) When mixing operators, enclose them in parentheses. The only exception is the standard arithmetic operators (`+`, `-`, `*`, & `/`) since their precedence is broadly understood. eslint: [`no-mixed-operators`](https://eslint.org/docs/rules/no-mixed-operators.html)
+  - [15.8](#comparison--no-mixed-operators) When mixing operators, enclose them in parentheses. The only exception is the standard arithmetic operators: `+`, `-`, and `**` since their precedence is broadly understood. We recommend enclosing `/` and `*` in parentheses because their precedence can be ambiguous when they are mixed.
+  eslint: [`no-mixed-operators`](https://eslint.org/docs/rules/no-mixed-operators.html)
 
     > Why? This improves readability and clarifies the developer’s intention.
 
@@ -2060,19 +2061,22 @@ Other Style Guides
       return d;
     }
 
+    // bad
+    const bar = a + b / c * d;
+
     // good
     const foo = (a && b < 0) || c > 0 || (d + 1 === 0);
 
     // good
-    const bar = (a ** b) - (5 % d);
+    const bar = a ** b - (5 % d);
 
     // good
     if (a || (b && c)) {
       return d;
     }
 
     // good
-    const bar = a + b / c * d;
+    const bar = a + (b / c) * d;
     ```
 
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packages/eslint-config-airbnb-base/rules/style.js

@@ -293,14 +293,10 @@ module.exports = {
         ['%', '-'],
         ['%', '*'],
         ['%', '/'],
-        ['**', '+'],
-        ['**', '-'],
-        ['**', '*'],
-        ['**', '/'],
-        ['&', '|', '^', '~', '<<', '>>', '>>>'],
-        ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
+        ['/', '*'],
+        ['&', '|', '<<', '>>', '>>>'],
+        ['==', '!=', '===', '!=='],
         ['&&', '||'],
-        ['in', 'instanceof']
       ],
       allowSamePrecedence: false
     }],