Run multiple git branches with PM2 - node.js

Question

I have an express application with three branches: master, staging, and development. I want to run all three branches simultaneously, each on a different port, i.e. master on 3000, staging on 3001, development on 3002.
I'm hoping to achieve this with PM2, but haven't been able to get this to work yet. I was trying with an ecosystem.config.yml like the one below, which successfully runs the application on ports 3000-3002 and injects the corresponding environment variables, but runs the code of the active branch on all three ports.
Is it possible configure PM2 to run different git branches on different ports? Maybe with the PM2 deploy command and associated configuration somehow?
module.exports = {
apps: [
{
name: "api",
script: "app.js",
watch: ".",
env: {
NODE_ENV: "production",
PORT: "3000",
},
},
{
name: "api-staging",
script: "app.js",
watch: ".",
env: {
NODE_ENV: "staging",
PORT: "3001",
},
},
{
name: "api-dev",
script: "app.js",
watch: ".",
env: {
NODE_ENV: "development",
PORT: "3002",
},
},
],
};

Answer 1

Answering my own question here. The only way I've found to easily do this is to make a local copy of each branch of my repo in its own directory using git clone --branch <branchname> --single-branch <remote-repo-url>, e.g. git clone --branch development --single-branch git#github.com:myuser/my-api.git api-dev to clone the development branch of my repo into a local directory /api-dev.
Then in each local directory, which contains a single branch of my repo, I create an ecosystem.config.js file with configuration appropriate for that branch, e.g.
module.exports = {
apps: [
{
name: "api-dev",
script: "app.js",
watch: ".",
env: {
NODE_ENV: "development",
PORT: "3002",
},
},
],
};
Then I can run pm2 start ecosystem.config.js in each of my local repositories and run each branch on its own port.
Does anyone know a simpler way to do this?