$ npm install

C:\Users\JJ\AppData\Roaming\npm\node_modules\npm\bin\npm-cli.js:79

      let notifier = require('update-notifier')({pkg})

      ^^^

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode

    at exports.runInThisContext (vm.js:53:16)

    at Module._compile (module.js:373:25)

    at Object.Module._extensions..js (module.js:416:10)

    at Module.load (module.js:343:32)

    at Function.Module._load (module.js:300:12)

    at Function.Module.runMain (module.js:441:10)

    at startup (node.js:139:18)

    at node.js:968:3