title: NPM outdated throws npm ERR! Not implemented yet
body: <p>Since I updated to npm 6.9.0 (node 8.12.0) I'm getting this error when running <code>npm outdated</code>:</p>
  
  <pre><code>$ npm outdated
  npm ERR! Not implemented yet
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     /Users/jgallaso/.npm/_logs/2019-04-10T11_13_48_791Z-debug.log
  </code></pre>
  
  <p>The logs shows this error:</p>
  
  <pre><code>173 verbose stack Error: Not implemented yet
  173 verbose stack     at Object.packument (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/pacote/lib/fetchers/remote.js:12:22)
  173 verbose stack     at Object.Fetcher#packument [as packument] (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/genfun/lib/genfun.js:15:38)
  173 verbose stack     at packument (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/pacote/lib/fetch.js:17:18)
  173 verbose stack     at pinflight (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/pacote/packument.js:23:12)
  173 verbose stack     at /Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/promise-inflight/inflight.js:29:24
  173 verbose stack     at Promise._execute (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/debuggability.js:313:9)
  173 verbose stack     at Promise._resolveFromExecutor (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/promise.js:483:18)
  173 verbose stack     at new Promise (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/promise.js:79:10)
  173 verbose stack     at _inflight (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/promise-inflight/inflight.js:28:25)
  173 verbose stack     at /Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/promise-inflight/inflight.js:22:14
  173 verbose stack     at tryCatcher (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/util.js:16:23)
  173 verbose stack     at Promise._settlePromiseFromHandler (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/promise.js:512:31)
  173 verbose stack     at Promise._settlePromise (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/promise.js:569:18)
  173 verbose stack     at Promise._settlePromiseCtx (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/promise.js:606:10)
  173 verbose stack     at _drainQueueStep (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/async.js:142:12)
  173 verbose stack     at _drainQueue (/Users/jgallaso/.nvm/versions/node/v8.12.0/lib/node_modules/npm/node_modules/bluebird/js/release/async.js:131:9)
  </code></pre>
  
  <p>When I run <code>npm outdated</code> on a specific package, for instance <code>eslint</code> I get the proper output:</p>
  
  <pre><code>$ npm outdated eslint
  Package  Current  Wanted  Latest  Location
  eslint    5.15.1  5.16.0  5.16.0
  </code></pre>
  
  <p>What's happening here? Is it due to some buggy package or a bug NPM itself?</p>