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

[effbiae]

$ nodejs --version
v4.2.6
ig-markets-master$ nodejs example.js
/home/jack/ig/ig-markets-master/lib/ig.js:3
let API = 'https://api.ig.com/gateway/deal/';
^^^

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:374:25)
at Object.Module._extensions..js (module.js:417:10)
at Module.load (module.js:344:32)
at Function.Module._load (module.js:301:12)
at Module.require (module.js:354:17)
at require (internal/module.js:12:17)
at Object. (/home/jack/ig/ig-markets-master/example.js:1:72)
at Module._compile (module.js:410:26)
at Object.Module._extensions..js (module.js:417:10)

[ottosson]

You should use a newer version of Node, or transpile to es5 using Babel or similar.