feat: Display a message if there are no files that match a pattern. (#…

…139)

* Adding logging for when no files match a pattern.
* Using Listr `skip` to skip tasks with empty file lists.

Closes #135

src/generateTasks.js

@@ -13,13 +13,10 @@ module.exports = function generateTasks(config, files) {
                 dot: true
             })
             const fileList = Object.keys(files).filter(filter).map(resolve)
-            if (fileList.length) {
-                return {
-                    pattern,
-                    commands,
-                    fileList
-                }
+            return {
+                pattern,
+                commands,
+                fileList
             }
-            return undefined
-        }).filter(Boolean) // Filter undefined values
+        })
 }

src/index.js

@@ -64,7 +64,13 @@ cosmiconfig('lint-staged', {
                                 exitOnError: true
                             }
                         )
-                    )
+                    ),
+                    skip: () => {
+                        if (task.fileList.length === 0) {
+                            return `No staged files match ${ task.pattern }`
+                        }
+                        return false
+                    }
                 }))
 
 

test/generateTasks.spec.js

@@ -58,17 +58,15 @@ describe('generateTasks', () => {
         ])
     })
 
-    it('should return only linters it could find files for', () => {
+    it('should return an empty file list for linters with no matches.', () => {
         const result = generateTasks(linters, files)
-        const commands = result.map(match => match.commands)
-        expect(commands).toEqual([
-            'root-js',
-            'any-js',
-            'deeper-js',
-            'hidden-js',
-            // 'unknown-js' does not match any files
-            'root-css-or-js'
-        ])
+        for (const task of result) {
+            if (task.commands === 'unknown-js') {
+                expect(task.fileList.length).toEqual(0)
+            } else {
+                expect(task.fileList.length).toNotEqual(0)
+            }
+        }
     })
 
     it('should match pattern "*.js"', () => {