Runtime error encountered: flags.trim is not a function after update to 2.8.0 to 2.9.1

[m2kannojiya]

Earlier I was using 2.8.0 and report was running fine but after update I am getting issue as given below.

lighthouse http://localhost:8080 --chrome-flags="--headless" --chrome-flags="--no-sandbox" --output json --output html --output-path ./reports/lighthouse/lighthouse.json

22:20:02 Starting up http-server, serving dist/retail
22:20:02 Available on:
22:20:02 http://127.0.0.1:8080
22:20:02 Hit CTRL-C to stop the server
22:20:03 Runtime error encountered: flags.trim is not a function
22:20:03 TypeError: flags.trim is not a function
22:20:03 at parseChromeFlags
/node_modules/lighthouse/lighthouse-cli/run.js:33:13)
22:20:03 at getDebuggableChrome
/node_modules/lighthouse/lighthouse-cli/run.js:58:18)
22:20:03 at chromeP.then._
/node_modules/lighthouse/lighthouse-cli/run.js:162:7)
22:20:03 at process._tickCallback (internal/process/next_tick.js:103:7)
22:20:03 at Module.runMain (module.js:606:11)
22:20:03 at run (bootstrap_node.js:394:7)
22:20:03 at startup (bootstrap_node.js:149:9)
22:20:03 at bootstrap_node.js:509:3
22:20:03
22:20:03 npm ERR! Linux 3.10.0-693.11.6.el7.x86_64
22:20:03 npm ERR! argv "/data/slave/jenkins/tools/jenkins.plugins.nodejs.tools.NodeJSInstallation/Node_6.10.0/bin/node" "/data/slave/jenkins/tools/jenkins.plugins.nodejs.tools.NodeJSInstallation/Node_6.10.0/lib/node_modules/npm/bin/npm-cli.js" "run" "lighthouse"

[patrickhulce]

This appears to be a regression caused by #4441, but honestly it is somewhat of an accident that it ever worked at all. --chrome-flags was never intended to be added multiple times, the expected usage for your case is --chrome-flags="--headless --no-sandbox" which still works in 2.9.1

I guess we'll need to decide if we want to officially support this or not.

[paulirish]

i'd prefer to not support --chrome-flags="--headless" --chrome-flags="--no-sandbox".

(though yargs would make this kinda ez with the .array() method. but still.. would prefer to avoid if we can.)