This repo was helpful https://github.com/Azure/azure-cosmos-js/blob/master/samples/ItemManagement/app.js
Sample local.settings.json:
{
"IsEncrypted": false,
"Values": {
"AzureWebJobsStorage": "DefaultEndpointsProtocol=https;AccountName=sa;AccountKey=/asdfasdfasdf/HPIz4cjylAP+g26tEKbfZSi2FBVeIDr708VcWL04/6F1KO1wspMXvCirTYjlY91tA==;EndpointSuffix=core.windows.net",
"FUNCTIONS_WORKER_RUNTIME": "node",
"cosmosEndpoint": "https://cosmos.documents.azure.com:443/",
"cosmosKey": "YNlpMSRAIYbPouQKFd0YKV0qf2zgbuN03Lxfs5xWb7huc5SbXpfQDRWuk7KhRXlD8CeY7oHsKUrjguJV2bBhOA==",
"myEventHubReadConnectionAppSetting" : "Endpoint=sb://iothub-spot-840786-a77bf29100.servicebus.windows.net/;SharedAccessKeyName=iothubowner;SharedAccessKey=vzWgVH34Jo3pQluCzWRx9nHvU2jWTMfVdfN/o8svtho=;EntityPath=hubp",
"MyAccount_COSMOSDB" : "AccountEndpoint=https://cosmosForYou.documents.azure.com:443/;AccountKey=YNlpMSRAIYbPouQKFd0YKV0qf2zgbuN03Lxfs5xWb7huc5SbXpfQDRWuk7KhRXlD8CeY7oHsKUrjguJV2bBhOA==;"
}
}