I am struggling with this error since yesterday : Cannot read properties of undefined (reading 'get').

I am using ftp NodeJS module. I have instanciated an c attribute in my class like this :

constructor(){
        this.fileFromFTP = '';
        this.fileFromShop = '';
        this.items = [];
        this.c = new Client();
    }

The error comes from this method, on the second line (this.c.get) :

refreshStore(){
      this.c.on('ready', function() {
        this.c.get('GCEvo/Product_mdl.csv', function(err, stream) {  
          if (err) throw err;

When I hover the this.c.get, I don't get a reference to my c attribute. How can I solve this ?

Thank you!