No best common type exists among return expressions

[hongbo-miao]

When I use try the code in the example in angular2-meteor,

createdAt: {
    type: Date,
    autoValue: function() {
      if (this.isInsert) {
        return new Date();
      } else if (this.isUpsert) {
        return {$setOnInsert: new Date()};
      } else {
        this.unset();
      }
    }
  }

it will give the warning:

No best common type exists among return expressions.

How about changing to this?

createdAt: {
    type: Date,
    autoValue: function() {
      if (this.isInsert) {
        return new Date();
      } else if (this.isUpsert) {
        return {$setOnInsert: new Date()};
      } else {
        this.unset();
        return undefined;  // <- add this line
      }
    }
  }

[hongbo-miao]

It is related with TypeScript, this is not correct way to avoid the warning. I need more time to confirm

[hongbo-miao]

Oh, I got solution here.