access nested variables and passing of undefined error in js

.js

// check for empty objects/variables
  isEmpty = value =>
    value === null ||
    value === undefined ||
    value === "undefined" ||
    value.length === 0 ||
    value === {};

// access the nested variables or return null if undifined or doesn't exist
  getNested = (p, o) => p.reduce((xs, x) => (!this.isEmpty(xs) && !this.isEmpty(xs[x]) ? xs[x] : null), o);