Chokidar isn't picking up file changes inside docker container - node.js

Question

I'm using docker for mac version 1.12.0-rc2 for a react project. My workflow is this:
src/ folder on OS X is mounted to the container
When a developer modifies a file in src/ it gets converted to ES5 and placed in public/ (this works).
When a file is changed in public/ another watcher triggers hot reloading (works on my localhost but not in the container).
Here's my step watcher code from step 3:
// root = "/src"
const watcher = chokidar.watch(root, {
usePolling: true,
awaitWriteFinish: {
pollInterval: 100,
stabilityThreshold: 250
},
ignored: /\.(git|gz|map)|node_modules|jspm_packages|src/,
ignoreInitial: true,
persistent: true
})
.on("change", function fileWatcher(filename) {
const modulePath = filename.replace(`${root}/`, "");
wss.clients.forEach(function sendFileChange(client) {
send("filechange", modulePath, client);
});
if (cache[filename]) {
wss.clients.forEach(function sendCacheFlush(client) {
send("cacheflush", filename, client);
});
delete cache[filename];
}
});
And my docker-compose.yml file:
version: '2'
services:
wildcat:
build:
context: .
args:
JSPM_GITHUB_AUTH_TOKEN:
image: "nfl/react-wildcat-example:latest"
environment:
NODE_ENV: development
PORT: 3000
STATIC_PORT: 4000
COVERAGE:
LOG_LEVEL:
NODE_TLS_REJECT_UNAUTHORIZED: 0
CHOKIDAR_USEPOLLING: 'true'
volumes:
- ./src:/src/src
- ./api:/src/api
ports:
- "3000:3000"
- "4000:4000"
ulimits:
nproc: 65535
entrypoint: "npm run"
command: "dev"

Answer 1

After spending a day or two on this I found the issue, the line:
ignored: /\.(git|gz|map)|node_modules|jspm_packages|src/,
Was causing chokidar to ignore /src which was the folder I was copying all the source code to in the docker container. I changed this path in the Dockerfile and docker-compose.yml to /code instead and everything worked as expected.

Answer 2

As a hopefully helpful note to those coming here by the title, Chokidar docs states:
It is typically necessary to set this (polling) to true to successfully watch files over a network, and it may be necessary to successfully watch files in other non-standard situations.
On Docker Desktop for Mac 4.0.0, I got Firebase Emulators (that uses Chokidar) to see host-side file changes by:
environments:
- CHOKIDAR_USEPOLLING=true