"Process is not defined" error while building react app about esbuild HOT 1 CLOSED

The way this works with esbuild is to use --define like this:

esbuild src/index.js--outfile=dist/index.js --bundle '--define:process.env.NODE_ENV="production"' 

This replaces all instances of process.env.NODE_ENV with the string "production". I have also included enough dead code elimination logic in esbuild to be able to handle cases like this. The code above will turn into this:

"use strict";
if (true) {
  module.exports = require(1172 /* ./cjs/react.production.min.js */);
} else {
  module.exports = null;
}

The require() call in the false branch turns into null because esbuild knows it's never executed, and should not be included in the bundle. If you also pass --minify that gives esbuild permission to compact the structure of your code, so it will then turn into this:

module.exports = require(1172 /* ./cjs/react.production.min.js */);

The --define feature can replace any identifier or member expression in your code, not just process.env.NODE_ENV.

from esbuild.