feat/issue-1398: added support for custom configuration

lib/makeCmdTasks.js

@@ -1,7 +1,8 @@
 import debug from 'debug'
 
 import { configurationError } from './messages.js'
-import { resolveTaskFn } from './resolveTaskFn.js'
+import { makeErr, resolveTaskFn } from './resolveTaskFn.js'
+import { getInitialState } from './state.js'
 
 const debugLog = debug('lint-staged:makeCmdTasks')
 
@@ -31,20 +32,47 @@ export const makeCmdTasks = async ({ commands, cwd, files, gitDir, shell, verbos
     const resolvedArray = Array.isArray(resolved) ? resolved : [resolved] // Wrap non-array command as array
 
     for (const command of resolvedArray) {
-      // If the function linter didn't return string | string[]  it won't work
+      // If the function linter didn't return string | string[] | object it won't work
       // Do the validation here instead of `validateConfig` to skip evaluating the function multiple times
-      if (isFn && typeof command !== 'string') {
+      if ((isFn && typeof command !== 'string' && typeof command !== 'object') || !command) {
         throw new Error(
           configurationError(
             '[Function]',
-            'Function task should return a string or an array of strings',
+            'Function task should return a string or an array of strings or an object',
             resolved
           )
         )
+      } else if (isFn && typeof command === 'object') {
+        if (
+          typeof command.title === 'string' &&
+          typeof command.command === 'string' &&
+          typeof command.task === 'function'
+        ) {
+          const task = async (ctx = getInitialState()) => {
+            try {
+              await command.task()
+            } catch (e) {
+              throw makeErr(command.title, e, ctx)
+            }
+          }
+          cmdTasks.push({
+            title: command.title,
+            command: command.command,
+            task,
+          })
+        } else {
+          throw new Error(
+            configurationError(
+              '[Function]',
+              'Function task should return object with title, command and task where title or command should be string and task should be function',
+              resolved
+            )
+          )
+        }
+      } else {
+        const task = resolveTaskFn({ command, cwd, files, gitDir, isFn, shell, verbose })
+        cmdTasks.push({ title: command, command, task })
       }
-
-      const task = resolveTaskFn({ command, cwd, files, gitDir, isFn, shell, verbose })
-      cmdTasks.push({ title: command, command, task })
     }
   }
 

lib/resolveTaskFn.js

@@ -108,7 +108,7 @@ const interruptExecutionOnError = (ctx, execaChildProcess) => {
  * @param {Object} ctx
  * @returns {Error}
  */
-const makeErr = (command, result, ctx) => {
+export const makeErr = (command, result, ctx) => {
   ctx.errors.add(TaskError)
 
   // https://nodejs.org/api/events.html#error-events

test/unit/makeCmdTasks.spec.js

@@ -112,14 +112,14 @@ describe('makeCmdTasks', () => {
     expect(res[0].title).toEqual('test')
   })
 
-  it("should throw when function task doesn't return string | string[]", async () => {
+  it("should throw when function task doesn't return string | string[] | object", async () => {
     await expect(makeCmdTasks({ commands: () => null, gitDir, files: ['test.js'] })).rejects
       .toThrowErrorMatchingInlineSnapshot(`
             "✖ Validation Error:
 
               Invalid value for '[Function]': null
 
-              Function task should return a string or an array of strings"
+              Function task should return a string or an array of strings or an object"
           `)
   })