Should functions in object literals be defined as prototypes?

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Javascript

I have the following js literal object prototype, and whenever I create multiple with Object.create, the methods of this object are also added to memory?

What I have tried:

edge_class = function( arg ){
    const name = arg;     
    return {
        display: function(){
            return name;
        },
        hide: function(){
             name = '';
        }
    }
}

var member = Object.create(edge_class('cat'));

When creating an object instance with Create.Object, does the function have to be defined separately as a prototype?

edge_class.prototype.display = function(){
    return this.name;
}