Repository: serverless/serverless-azure-functions (ts)

Issue:
Listing Deployments: TypeError: Cannot convert undefined or null to object error
# This is a Bug Report

## Description

When attempting to deploy to Azure I'm getting a TypeError when the plugin is checking previous deployment templates.

```
TypeError: Cannot convert undefined or null to object
      at Function.keys (<anonymous>)
      at paramsNormalizer (/Users/brucestorrie/drds/azuretest/drdsfuncs/node_modules/serverless-azure-functions/lib/services/armService.js:259:31)
      at ArmService.areDeploymentsEqual (/Users/brucestorrie/drds/azuretest/drdsfuncs/node_modules/serverless-azure-functions/lib/services/armService.js:276:80)
      at ArmService.<anonymous> (/Users/brucestorrie/drds/azuretest/drdsfuncs/node_modules/serverless-azure-functions/lib/services/armService.js:193:34)
      at step (/Users/brucestorrie/drds/azuretest/drdsfuncs/node_modules/serverless-azure-functions/lib/services/armService.js:56:23)

```

## Additional Data

I've debugged the issue and identified that it's because the previous deployment template did not contain any parameters but there is a check within the code to compare templates which isn't catering for that scenario.




Pull request description:
fix: Hot fix for undefined params
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## What did you implement:

Closes #410 

## How did you implement it:

Checked if params were undefined, return empty object if they are.

## How can we verify it:

Redeploy a function app that previously had no parameters. It used to be broken, now it's not :)

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## Todos:

_**Note: Run `npm run test:ci` to run all validation checks on proposed changes**_

- [x] Ensure there are no lint errors.  
       **Validate via `npm run lint`**  
       _Note: Some reported issues can be automatically fixed by running `npm run lint:fix`_
- [x] Write tests and confirm existing functionality is not broken.  
       **Validate via `npm test`**
- [x] Write documentation
- [x] Provide verification config / commands / resources
- [x] Enable "Allow edits from maintainers" for this PR
- [x] Update the messages below

**_Is this ready for review?:_** YES 
**_Is it a breaking change?:_** NO


Patch:
diff --git a/src/services/armService.ts b/src/services/armService.ts
index f64f7e4..e967fa2 100644
--- a/src/services/armService.ts
+++ b/src/services/armService.ts
@@ -101,6 +101,8 @@ export class ArmService extends BaseService {
       return;
     }
 
+    deployment.parameters = deployment.parameters || {};
+    
     for (const key of Object.keys(deployment.parameters)) {
       if (!deployment.parameters[key].value) {
         delete deployment.parameters[key];
@@ -160,6 +162,9 @@ export class ArmService extends BaseService {
 
     const paramsNormalizer = (params: ArmParameters): ArmParameters => {
       const normalized = {};
+      if (!params) {
+        return normalized;
+      }
       const keys = Object.keys(params);
       for (const key of keys) {
         const original = params[key];
@@ -207,6 +212,8 @@ export class ArmService extends BaseService {
    */
   private mergeDefaultParams(parameters: ArmParameters, defaultParameters: ArmParameters): ArmParameters {
     const mergedParams: ArmParameters = {}
+    parameters = parameters || {};
+    defaultParameters = defaultParameters || {};
     Object.keys(defaultParameters).forEach((key) => {
       const defaultParam = defaultParameters[key];
       const param = parameters[key];


Test patch:
diff --git a/src/services/armService.test.ts b/src/services/armService.test.ts
index d2baa30..c0283cc 100644
--- a/src/services/armService.test.ts
+++ b/src/services/armService.test.ts
@@ -167,7 +167,16 @@ describe("Arm Service", () => {
         template: MockFactory.createTestArmTemplate()
       };
       await service.deployTemplate(deployment);
-      expect(Deployments.prototype.createOrUpdate).not.toBeCalled()
+      expect(Deployments.prototype.createOrUpdate).not.toBeCalled();
+    });
+
+    it("Does not crash if deployment parameters are undefined", async () => {
+      const deployment: ArmDeployment = {
+        parameters: undefined,
+        template: MockFactory.createTestArmTemplate(),
+      };
+      await service.deployTemplate(deployment);
+      expect(Deployments.prototype.createOrUpdate).toBeCalled();
     });
 
     it("Does not deploy if identity is only difference between deployments", async () => {