Only use the last output buffer from the deploy execute command

[stewart42]

Hi there, I have created this PR to highlight a fix I needed to implement in order to get the action to complete successfully with our current build and deploy action:

The error below (raw logs):

020-09-14T15:15:52.5567756Z ##[group]Run FirebaseExtended/action-hosting-deploy@v0
2020-09-14T15:15:52.5568356Z with:
2020-09-14T15:15:52.5569194Z   repoToken: ***
2020-09-14T15:15:52.5593505Z   firebaseServiceAccount: ***

2020-09-14T15:15:52.5594134Z   projectId: <removed>
2020-09-14T15:15:52.5594608Z   expires: 7d
2020-09-14T15:15:52.5595023Z   entryPoint: .
2020-09-14T15:15:52.5595402Z env:
2020-09-14T15:15:52.5595879Z   FIREBASE_CLI_PREVIEWS: hostingchannels
2020-09-14T15:15:52.5596389Z ##[endgroup]
2020-09-14T15:15:52.9027131Z ##[group]Verifying firebase.json exists
2020-09-14T15:15:52.9032334Z firebase.json file found. Continuing deploy.
2020-09-14T15:15:52.9033813Z ##[endgroup]
2020-09-14T15:15:52.9034864Z ##[group]Setting up CLI credentials
2020-09-14T15:15:52.9056253Z Created a temporary file with Application Default Credentials.
2020-09-14T15:15:52.9057065Z ##[endgroup]
2020-09-14T15:15:52.9059141Z ChannelId "pr1117-devops/preview-chann" contains unsupported characters. Using "pr1117-devops_preview-chann" instead.
2020-09-14T15:15:52.9061241Z ##[group]Deploying to Firebase preview channel pr1117-devops_preview-chann
2020-09-14T15:15:52.9125011Z [command]/opt/hostedtoolcache/node/12.18.3/x64/bin/npx firebase-tools hosting:channel:deploy pr1117-devops_preview-chann --project <removed> --json
2020-09-14T15:16:21.8119554Z �[2K�[9999D***
2020-09-14T15:16:21.8120456Z   "status": "success",
2020-09-14T15:16:21.8121114Z   "result": ***
2020-09-14T15:16:21.8121705Z     "<removed>": ***
2020-09-14T15:16:21.8123270Z       "site": "<removed>",
2020-09-14T15:16:21.8123801Z       "target": "over",
2020-09-14T15:16:21.8125374Z       "url": "<removed>",
2020-09-14T15:16:21.8127228Z       "expireTime": "2020-09-21T15:16:15.792976521Z"
2020-09-14T15:16:21.8127662Z     ***,
2020-09-14T15:16:21.8128008Z     "<removed>": ***
2020-09-14T15:16:21.8128662Z       "site": "<removed>",
2020-09-14T15:16:21.8129233Z       "target": "godaddy",
2020-09-14T15:16:21.8131101Z       "url": "https://<removed>.web.app",
2020-09-14T15:16:21.8132773Z       "expireTime": "2020-09-21T15:16:15.762875096Z"
2020-09-14T15:16:21.8133180Z     ***
2020-09-14T15:16:21.8133480Z   ***
2020-09-14T15:16:21.8133794Z ***
2020-09-14T15:16:22.9545360Z 
2020-09-14T15:16:22.9549418Z ##[error]Unexpected token � in JSON at position 0

As you can see there are additional characters \x1B[2K\x1B[9999D (base64 value G1sySxtbOTk5OUQ=) at the beginning of the output, this leads to the failure of the JSON.parse call. While debugging I determined that it was always the first push into the buffer array variable on line 70 that had these odd characters. Where these characters come from I am not sure. I didn't want to alter the code too much, and rather just changed the return value of the function to on return the last buffer in the array which appears to consistently have the JSON output.

Thanks for making this action! Other than this odd issue it has been working great!

[jhuleatt]

Thank you for this fix @stewart42!