$ 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