NodeJs Lambda Layers and webpack (without serverless) - node.js

Question

I've got a lambda function which is connecting to some layers. It's built using nodejs/typescript and I'm trying to get it built using webpack.
My problem is that I can't seem to figure out how to package the app using webpack with my layer module imports.
For example, I have a reference like this in my application:
import { ProductEntity, IProduct, productEntityManager } from "/opt/nodejs/orm";
If I try to run webpack normally, i'll get a Module not found error saying it can't find "/opt/nodejs/orm".
So I've added in the ignore plugin as below:
"use strict";
const path = require("path");
const webpack = require('webpack')
const ignore = new webpack.IgnorePlugin({resourceRegExp:/^(\/opt\/nodejs\/search|\/opt\/nodejs\/orm|\/opt\/nodejs\/put-event)$/})
module.exports = {
devtool: "source-map",
entry: "./src/handler.ts",
mode: "production",
target: "node",
plugins: [ignore],
node: {
__dirname: true,
},
output: {
filename: "index.js",
libraryTarget: "commonjs2",
path: path.resolve(__dirname, ".build"),
},
module: {
rules: [
{
test: /\.(graphql|gql)$/,
loader: "graphql-tag/loader",
exclude: /node_modules/,
},
{
test: /\.(tsx?)$/,
loader: "ts-loader",
exclude: [
[
path.resolve(__dirname, "node_modules"),
path.resolve(__dirname, ".serverless"),
path.resolve(__dirname, ".webpack")
],
],
options: {
transpileOnly: false,
experimentalWatchApi: true,
},
},
],
},
resolve: {
extensions: [".ts", ".tsx", ".js"],
},
};
And now I get the same error, but it's just baked in to my packaged js file.
I get something like this appear in that bundled js file:
...
var e=new Error("Cannot find module '/opt/nodejs/orm'")
...
So my question is... How do I build my lambda function using webpack and get it to not try and resolve or import the lambda layer modules?
I can see a lot of examples using serverless but I'm not using it (and not planning to because I'm using terraform).