用Javascript设置后，类变量仍未定义

Question

I'm relatively new to Javascript and I can't seem to figure out why sessionToken isn't getting set. When I console.log() it I get undefined even though I have just set it. What am I doing wrong?

class Service extends Backend {

  initialize(token) {
    if (!_.isNull(token) && _.isUndefined(token.sessionToken)) {
      throw new Error('Token missing');
    }
    this.sessionToken = _.isNull(token)
      ? null
      : token.sessionToken.access_token;

    console.log(this.sessionToken);

    this.API_BASE_URL = CONFIG.backend.serviceLocal
      ? CONFIG.SERVICE.local.url
      : CONFIG.SERVICE.remote.url;

    this.CLIENT_ID = CONFIG.backend.serviceLocal
      ? CONFIG.SERVICE.local.client_id
      : CONFIG.SERVICE.remote.client_id;
  }
}

Answer 1

this.sessionToken = _.isNull(token)
  ? null
  : token.sessionToken.access_token;

as said in the comment by Bulent Vural you're only checking if token exists and then assume that if it does also access_token is there. Seems that it is not the case and you get undefined. I mocked your code here and if you don't pass access_token it will indeed fail with undefined. Maybe time to write some unit tests ? :)

Answer 2

Seems like you only care about the access_token . Why not throw if that's not defined?

Try to write your function like this:

 initialize(token) { if (!(token && token.sessionToken && token.sessionToken.access_token)) { throw new Error('Access token missing'); } this.sessionToken = token.sessionToken.access_token; console.log(this.sessionToken); }