Realisation Stack on js

Stack.js

class Stack extends Array {
    constructor(STACKSIZE = Number.MAX_SAFE_INTEGER, ...arg) {
        super(...arg);
        
        Object.defineProperty(this, 'STACKSIZE', {
            value: STACKSIZE
        })
        
        this.push = this.push.bind(this);
        this.pop = this.pop.bind(this);
    }

    push(value) {
        if(this.length === this.STACKSIZE) {
            let error = new Error("Stack overflow\n");
            error.name = 'Stack Error';
            
            return error.toString();
        }
        return super.push(value);
    }

    pop() {
        if(this.length === 0) {
            let error = new Error("Stack underflow\n");
            error.name = 'Stack Error';
            
            return error.toString();
        }

        return this.splice(-1,1);
    }
}