vue-cli 3.1.0 how to import commonjs module into typescript component

Question

I'm trying to import some legacy code in commonjs format into a typescript translation unit that is associated with a vanilla-ish project created by vue-cli 3.1.0. The error I'm getting is from webpack. It appears that the typescript component wants to consume modules in ES6 format:

ReferenceError: exports is not defined
cjs_module.js:3
    at Module../src/cjs_module.js (/Users/skelly/dev/nimbee/edu/js/app/wmadmin_dashboard/src/cjs_module.js:3:1)
    at __webpack_require__ (http://10.0.9.2:8080/app.js:725:30)

The tsconfig.json is below:

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "strict": true,
    "noUnusedLocals": false,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "jsx": "preserve",
    "importHelpers": true,
    "moduleResolution": "node",
    "experimentalDecorators": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "composite": true
  },
  "lib": [
    "esnext",
    "dom",
    "dom.iterable",
    "scripthost"
  ],
  "exclude": [
    "node_modules"
  ]
}

There are other configs in play such as vue.config.js and babel.config.js. I'm new to the vue JS ecosystem so thanks for entertaining a newb question.

I should add the module I'm experimenting with is:

// works
export const a = 'es6 module';
// doesn't work
//exports.a= 'cjs_module';
var regexp = new RegExp('blah');

The import syntax in typescript I'm using is:

const cjs_module = require('./cjs_module');
console.log(cjs_module.a);