title: Unable to load Node backend for Tensorflow (TypeError: Cannot read property 'nonMaxSuppressionV3Impl' of undefined)
body: <p>I'm trying to use face-api.js facial recognition functions, which would run a lot faster with an installed Node backend. I've installed the backends with npm as below:</p>
  <pre><code>$ node -v
  v14.1.0
  $ npm list @tensorflow/tfjs-node
  appname@0.1.0 /Users/akoi/Dev/bwr
  └── @tensorflow/tfjs-node@2.3.0 
  $ npm list @tensorflow/tfjs
  appname@0.1.0 /Users/akoi/Dev/bwr
  ├── @tensorflow/tfjs@2.3.0 
  ├─┬ @tensorflow/tfjs-node@2.3.0
  │ └── @tensorflow/tfjs@2.3.0  deduped
  └─┬ @tensorflow/tfjs-node-gpu@2.3.0
    └── @tensorflow/tfjs@2.3.0  deduped
  </code></pre>
  <p>The face-api.js functions all work fine, just slow since the backend is not loading.</p>
  <p>When I do attempt to load the backend according to the instructions, using:</p>
  <pre><code>require('@tensorflow/tfjs-node');
  </code></pre>
  <p>Here is the error I get when run:</p>
  <pre><code>TypeError: Cannot read property 'nonMaxSuppressionV3Impl' of undefined
      at Object.&lt;anonymous&gt; (/Users/akoi/Dev/bwr/node_modules/@tensorflow/tfjs-backend-cpu/dist/tf-backend-cpu.node.js:268:47)
      at Module._compile (internal/modules/cjs/loader.js:1176:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:1196:10)
      at Module.load (internal/modules/cjs/loader.js:1040:32)
      at Function.Module._load (internal/modules/cjs/loader.js:929:14)
      at Module.require (internal/modules/cjs/loader.js:1080:19)
      at require (internal/modules/cjs/helpers.js:72:18)
      at Object.&lt;anonymous&gt; (/Users/akoi/Dev/bwr/node_modules/@tensorflow/tfjs/dist/tf.node.js:25:22)
      at Module._compile (internal/modules/cjs/loader.js:1176:30)
      at Object.Module._extensions..js (internal/modules/cjs/loader.js:1196:10)
  </code></pre>
  <p>Any ideas? I've seen a similar issue raised last week, but no responses. All help and advice appreciated. Many thanks.</p>