From 28a5372a94c6c6c02177413c82e77c4d390e3f03 Mon Sep 17 00:00:00 2001
From: Francois Best <francois@francoisbest.com>
Date: Thu, 20 Jan 2022 22:16:52 +0100
Subject: [PATCH] feat: Add support for conditional jobs declaration

By ignoring falsy values in the jobs array.
---
 README.md         | 20 ++++++++++++++++++++
 src/index.test.ts | 17 +++++++++++++++++
 src/index.ts      |  8 ++++++--
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 3cdb151..39cd51e 100644
--- a/README.md
+++ b/README.md
@@ -207,6 +207,26 @@ if (process.env.INSTANCE_NUMBER === 0) {
 }
 ```
 
+## Conditionally running jobs
+
+You may want to run certain jobs in development only, or under other conditions.
+
+`fastify-cron` will ignore any falsy values in the `jobs` array, so you can do:
+
+```ts
+server.register(fastifyCron, {
+  jobs: [
+    process.env.ENABLE_DEV_JOB === 'true' && {
+      name: 'devJob',
+      cronTime: '* * * * *',
+      onTick: server => {
+        // ...
+      }
+    }
+  ]
+})
+```
+
 ## Compatibility Notes
 
 Some compatibility issues may arise with the [`cron` API](https://github.com/kelektiv/node-cron#api).
diff --git a/src/index.test.ts b/src/index.test.ts
index 353c0c3..2c38e31 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -112,4 +112,21 @@ describe('Creating jobs manually after registration', () => {
     expect(job).toBeDefined()
     expect(job!.running).toBeFalsy()
   })
+
+  test('falsy values are ignored in the jobs array', async () => {
+    const server = Fastify({ logger: false })
+    const spy = jest.fn()
+    await server.register(fastifyCron, {
+      jobs: [
+        false && {
+          name: 'foo',
+          cronTime: '* * * * *',
+          onTick: spy
+        }
+      ]
+    })
+    await server.ready()
+    const job = server.cron.getJobByName('foo')
+    expect(job).toBeUndefined()
+  })
 })
diff --git a/src/index.ts b/src/index.ts
index e8a07ad..f9fa6f9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -27,8 +27,10 @@ export interface CronDecorator {
   stopAllJobs: () => void
 }
 
+export type FalsyValue = undefined | null | false
+
 export interface Config {
-  jobs?: Params[]
+  jobs?: (Params | FalsyValue)[]
 }
 
 const plugin: FastifyPluginAsync<Config> = async function fastifyCronPlugin(
@@ -66,7 +68,9 @@ const plugin: FastifyPluginAsync<Config> = async function fastifyCronPlugin(
     }
   }
   for (const params of opts.jobs || []) {
-    decorator.createJob(params)
+    if (params) {
+      decorator.createJob(params)
+    }
   }
 
   server.decorate('cron', decorator)