Produced values of output of hasTruncated is confusing

[rqman]

In case of using input watchChanges and too long text on each update hasTruncated - will produce two values.

• First value emited after acutal value change.
• The second will be emitted after line-truncation finish work and provide truncated value to DOM.
  So hasTruncated will emit isTruncated = false however actually text has been truncated.

Environment: See example

• Editor that allow to write a long notes.
• Note preview should display a few first lines.
• Allow view all note's text by clicking on show more/ show less.

Step to reproduce:

• Change text into textarea (Text should have enought symbols to apply truncation)
• Press Save / sync changes button

Expected behavior:

• hasTruncated - should emit one value true

Actual Behaviour:

• hasTruncated - emitted true
• hasTruncated - emitted false