feat: add footer rules

Author: marionebl

documentation/rules.md

@@ -33,51 +33,70 @@ Rule configurations are either of type `array` residing on a key with the rule's
 
 
 ### Available rules
-#### type-enum
-* **condition**: `type` is found in value
+#### body-leading-blank
+* **condition**: `body` begins with blank line
+* **rule**: `always`
+
+#### body-max-length
+* **condition**: `body` has `value` or less characters
 * **rule**: `always`
 * **value**
-  ```js
-    [
-      'feat',
-      'fix',
-      'docs',
-      'style',
-      'refactor',
-      'test',
-      'chore',
-      'revert'
-    ]
-  ```
+```js
+  Infinity
+```
 
-#### type-case
-* **description**: `type` is in case `value`
+#### body-min-length
+* **condition**: `body` has `value` or more characters
 * **rule**: `always`
 * **value**
-  ```js
-    'lowerCase'
-  ```
+```js
+  0
+```
 
-#### type-empty
-* **condition**: `type` is empty
-* **rule**: `never`
+#### footer-leading-blank
+* **condition**: `footer` begins with blank line
+* **rule**: `always`
 
-#### type-max-length
-* **condition**: `type` has `value` or less characters
+#### footer-max-length
+* **condition**: `footer` has `value` or less characters
 * **rule**: `always`
 * **value**
 ```js
   Infinity
 ```
 
-#### type-min-length
-* **condition**: `type` has `value` or more characters
+#### footer-min-length
+* **condition**: `footer` has `value` or more characters
+* **rule**: `always`
+* **value**
+```js
+  0
+```
+
+#### header-max-length
+* **condition**: `header` has `value` or less characters
+* **rule**: `always`
+* **value**
+```js
+  72
+```
+
+#### header-min-length
+* **condition**: `header` has `value` or more characters
 * **rule**: `always`
 * **value**
 ```js
   0
 ```
 
+#### lang
+* **condition**: `subject` is of language `value`
+* **rule**: `always`
+* **value**
+```js
+  eng
+```
+
 #### scope-enum
 * **condition**: `scope` is found in value
 * **rule**: `always`
@@ -148,49 +167,51 @@ Rule configurations are either of type `array` residing on a key with the rule's
   '.'
 ```
 
-#### body-leading-blank
-* **condition**: `body` begins with blank line
-* **rule**: `always`
-
-#### body-max-length
-* **condition**: `body` has `value` or less characters
+#### type-enum
+* **condition**: `type` is found in value
 * **rule**: `always`
 * **value**
-```js
-  Infinity
-```
+  ```js
+    [
+      'feat',
+      'fix',
+      'docs',
+      'style',
+      'refactor',
+      'test',
+      'chore',
+      'revert'
+    ]
+  ```
 
-#### body-min-length
-* **condition**: `body` has `value` or more characters
+#### type-case
+* **description**: `type` is in case `value`
 * **rule**: `always`
 * **value**
-```js
-  0
-```
+  ```js
+    'lowerCase'
+  ```
 
-#### header-max-length
-* **condition**: `header` has `value` or less characters
+#### type-empty
+* **condition**: `type` is empty
+* **rule**: `never`
+
+#### type-max-length
+* **condition**: `type` has `value` or less characters
 * **rule**: `always`
 * **value**
 ```js
-  72
+  Infinity
 ```
 
-#### header-min-length
-* **condition**: `header` has `value` or more characters
+#### type-min-length
+* **condition**: `type` has `value` or more characters
 * **rule**: `always`
 * **value**
 ```js
   0
 ```
 
-#### lang
-* **condition**: `subject` is of language `value`
-* **rule**: `always`
-* **value**
-```js
-  eng
-```
 
 ### Wildcards
 The following rules identify commits that pass linting by skipping all other rules.

source/rules/footer-empty.js

@@ -0,0 +1,15 @@
+import ensureNotEmpty from '../library/ensure-not-empty';
+
+export default (parsed, when) => {
+	const negated = when === 'never';
+	return [
+		ensureNotEmpty(parsed.footer),
+		[
+			'footer',
+			negated ? 'may not' : 'must',
+			'be empty'
+		]
+		.filter(Boolean)
+		.join(' ')
+	];
+};

source/rules/footer-leading-blank.js

@@ -0,0 +1,20 @@
+export default (parsed, when) => {
+	const negated = when === 'never';
+	// get complete body split into lines
+	const lines = (parsed.raw || '').split('\n').slice(2);
+	// check if the first line of body (if any) is empty
+	const leadingBlank =
+		lines.length > 0 ?
+		lines[0].length === 0 :
+		true;
+	return [
+		negated ? !leadingBlank : leadingBlank,
+		[
+			'footer',
+			negated ? 'may not' : 'must',
+			'have leading blank line'
+		]
+		.filter(Boolean)
+		.join(' ')
+	];
+};

source/rules/footer-max-length.js

@@ -0,0 +1,8 @@
+import ensureMaxLength from '../library/ensure-max-length';
+
+export default (parsed, when, value) => {
+	return [
+		ensureMaxLength(parsed.footer, value),
+		`footer must not be longer than ${value} characters`
+	];
+};

source/rules/footer-min-length.js

@@ -0,0 +1,8 @@
+import ensureMinLength from '../library/ensure-min-length';
+
+export default (parsed, when, value) => {
+	return [
+		ensureMinLength(parsed.footer, value),
+		`footer must not be shorter than ${value} characters`
+	];
+};