como usar o hasKey no javascript es6

January 04, 2020

Returns true if the target value exists in a JSON object, false otherwise.

Check if keys is non-empty and use Array.prototype.every() to sequentially check its keys to internal depth of the object, obj. Use Object.prototype.hasOwnProperty() to check if obj does not have the current key or is not an object, stop propagation and return false. Otherwise assign the key’s value to obj to use on the next iteration. Return false beforehand if given key list is empty.

const hasKey = (obj, keys) => {
  return (
    keys.length > 0 &&
    keys.every(key => {
      if (typeof obj !== 'object' || !obj.hasOwnProperty(key)) return false;
      obj = obj[key];
      return true;
    })
  );
};

let obj = {
  a: 1,
  b: { c: 4 },
  'b.d': 5
};
hasKey(obj, ['a']); // true
hasKey(obj, ['b']); // true
hasKey(obj, ['b', 'c']); // true
hasKey(obj, ['b.d']); // true
hasKey(obj, ['d']); // false
hasKey(obj, ['c']); // false
hasKey(obj, ['b', 'f']); // false

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