Ionic 3 native-storage error code : 2, no detailed description

Question

I had an error when I used Ionic3's native-storage. It couldn't read the data in native-storage correctly. The error code: 2, but there was no detailed description.

  public async getToken(): Promise<AccessToken> {
    let token = null;
    let expires = null;
    try{
      token = await this.storage.getItem(this.ACCESSTOKEN_KEY);
      expires = await this.storage.getItem(this.ACCESSTOKEN_EXPIRES_KEY);
    }catch(e){
      alert(JSON.stringify(e));
    }
    if (token == null || expires == null || expires < new Date()) {
      token = null;
    }
    return token;
  }

Error screenshot:

Answer 1

Error codes contains an integer which specifies the occurred error:

• NATIVE_WRITE_FAILED = 1
• ITEM_NOT_FOUND = 2
• NULL_REFERENCE = 3
• UNDEFINED_TYPE = 4
• JSON_ERROR = 5
• WRONG_PARAMETER = 6