VSCode: run task on open

Hit Ctrl+Shift+B and select Configure build task > Create tasks.json from template > Other.

Now edit tasks.json and and put something like this:

{
	"version": "2.0.0",
	"tasks": [
		{
			"type": "npm",
			"script": "dev",
			"group": "build",
			"problemMatcher": [],
			"label": "npm: dev",
			"detail": "Serve",
			"runOptions": {
				"runOn": "folderOpen"
			}
		}
	]
}

Use "type": "shell" to run a shell command.