New: Add rule schemas (refs #2179)

docs/developer-guide/working-with-rules.md

@@ -21,6 +21,10 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    // JSON Schema for rule options goes here
+];
 ```
 
 **Important:** Rule submissions will not be accepted unless they are in this format.
@@ -132,6 +136,34 @@ Since `context.options` is just an array, you can use it to determine how many o
 
 When using options, make sure that your rule has some logic defaults in case the options are not provided.
 
+### Options Schemas
+
+Rules may export a `schema` property, which is a [JSON schema](http://json-schema.org/) format description of a rule's options which will be used by ESLint to validate configuration options and prevent invalid or unexpected inputs before they are passed to the rule in `context.options`.
+
+There are two formats for a rule's exported `schema`. The first is a full JSON Schema object describing all possible options the rule accepts, including the rule's error level as the first argument and any optional arguments thereafter.
+
+However, to simplify schema creation, rules may also export an array of schemas for each optional positional argument, and ESLint will automatically validate the required error level first. For example, the `yoda` rule accepts a primary mode argument, as well as an extra options object with named properties.
+
+```js
+// "yoda": [2, "never", { "exceptRange": true }]
+module.exports.schema = [
+    {
+        "enum": ["always", "never"]
+    },
+    {
+        "type": "object",
+        "properties": {
+            "exceptRange": {
+                "type": "boolean"
+            }
+        },
+        "additionalProperties": false
+    }
+];
+```
+
+In the preceding example, the error level is assumed to be the first argument. It is followed by the first optional argument, a string which may be either `"always"` or `"never"`. The final optional argument is an object, which may have a Boolean property named `exceptRange`.
+
 ### Getting the Source
 
 If your rule needs to get the actual JavaScript source to work with, then use the `context.getSource()` method. This method works as follows:

lib/rules/block-scoped-var.js

@@ -316,3 +316,5 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [];

lib/rules/brace-style.js

@@ -211,3 +211,18 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["1tbs", "stroustrup"]
+    },
+    {
+        "type": "object",
+        "properties": {
+            "allowSingleLine": {
+                "type": "boolean"
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/camelcase.js

@@ -97,3 +97,15 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "object",
+        "properties": {
+            "properties": {
+                "enum": ["always", "never"]
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/comma-dangle.js

@@ -56,3 +56,9 @@ module.exports = function (context) {
         "ArrayExpression": checkForTrailingComma
     };
 };
+
+module.exports.schema = [
+    {
+        "enum": ["always", "always-multiline", "never"]
+    }
+];

lib/rules/comma-spacing.js

@@ -174,3 +174,18 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "object",
+        "properties": {
+            "before": {
+                "type": "boolean"
+            },
+            "after": {
+                "type": "boolean"
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/comma-style.js

@@ -175,3 +175,21 @@ module.exports = function(context) {
 
     return nodes;
 };
+
+module.exports.schema = [
+    {
+        "enum": ["first", "last"]
+    },
+    {
+        "type": "object",
+        "properties": {
+            "exceptions": {
+                "type": "object",
+                "additionalProperties": {
+                    "type": "boolean"
+                }
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/complexity.js

@@ -86,3 +86,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "integer"
+    }
+];

lib/rules/consistent-return.js

@@ -71,3 +71,5 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [];

lib/rules/consistent-this.js

@@ -106,3 +106,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "string"
+    }
+];

lib/rules/curly.js

@@ -101,3 +101,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["all", "multi", "multi-line"]
+    }
+];

lib/rules/default-case.js

@@ -62,3 +62,5 @@ module.exports = function(context) {
         }
     };
 };
+
+module.exports.schema = [];

lib/rules/dot-notation.js

@@ -102,3 +102,18 @@ module.exports = function(context) {
         }
     };
 };
+
+module.exports.schema = [
+    {
+        "type": "object",
+        "properties": {
+            "allowKeywords": {
+                "type": "boolean"
+            },
+            "allowPattern": {
+                "type": "string"
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/eol-last.js

@@ -34,3 +34,5 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [];

lib/rules/eqeqeq.js

@@ -88,3 +88,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["smart", "allow-null"]
+    }
+];

lib/rules/func-names.js

@@ -41,3 +41,5 @@ module.exports = function(context) {
         }
     };
 };
+
+module.exports.schema = [];

lib/rules/func-style.js

@@ -41,3 +41,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["declaration", "expression"]
+    }
+];

lib/rules/generator-star-spacing.js

@@ -79,3 +79,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["before", "after", "both", "neither"]
+    }
+];

lib/rules/generator-star.js

@@ -68,3 +68,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["start", "middle", "end"]
+    }
+];

lib/rules/global-strict.js

@@ -41,3 +41,9 @@ module.exports = function(context) {
     }
 
 };
+
+module.exports.schema = [
+    {
+        "enum": ["always", "never"]
+    }
+];

lib/rules/guard-for-in.js

@@ -28,3 +28,5 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [];

lib/rules/handle-callback-err.js

@@ -116,3 +116,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "string"
+    }
+];

lib/rules/indent.js

@@ -462,3 +462,25 @@ module.exports = function (context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "oneOf": [
+            {
+                "enum": ["tab"]
+            },
+            {
+                "type": "integer"
+            }
+        ]
+    },
+    {
+        "type": "object",
+        "properties": {
+            "indentSwitchCase": {
+                "type": "boolean"
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/key-spacing.js

@@ -305,3 +305,21 @@ module.exports = function(context) {
     }
 
 };
+
+module.exports.schema = [
+    {
+        "type": "object",
+        "properties": {
+            "align": {
+                "enum": ["colon", "value"]
+            },
+            "beforeColon": {
+                "type": "boolean"
+            },
+            "afterColon": {
+                "type": "boolean"
+            }
+        },
+        "additionalProperties": false
+    }
+];

lib/rules/linebreak-style.js

@@ -36,3 +36,9 @@ module.exports = function (context) {
         }
     };
 };
+
+module.exports.schema = [
+    {
+        "enum": ["unix", "windows"]
+    }
+];

lib/rules/max-depth.js

@@ -81,3 +81,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "integer"
+    }
+];

lib/rules/max-len.js

@@ -32,9 +32,9 @@ module.exports = function(context) {
         return result;
     }
 
-    var tabWidth = context.options[1];
+    var tabWidth = context.options[1] || 4;
 
-    var maxLength = context.options[0],
+    var maxLength = context.options[0] || 80,
         tabString = stringRepeat(" ", tabWidth);
 
     //--------------------------------------------------------------------------
@@ -63,3 +63,14 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "integer",
+        "minimum": 0
+    },
+    {
+        "type": "integer",
+        "minimum": 0
+    }
+];

lib/rules/max-nested-callbacks.js

@@ -65,3 +65,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "integer"
+    }
+];

lib/rules/max-params.js

@@ -37,3 +37,9 @@ module.exports = function(context) {
     };
 
 };
+
+module.exports.schema = [
+    {
+        "type": "integer"
+    }
+];