Error found in zipped file.
nrtest3-code.zip
code/js_integration/01/app/javascript/packs/project.js

 44  taskId() {
 45     return this.$rowElement.data("TaskId")  <<<<<<< INCORRECT
 46   }

 44  taskId() {
 45     return this.$rowElement.data("link-id")  <<<<<<< CORRECT
 46   }

Also, the corresponding code sample in the main text has the same error.
Chapter 9 Testing JavaScript
section: Making the Test Pass

  taskId() {
    return this.$rowElement.data("taskId")  <<<<< needs to be "link-id"
  }

js_integration/01/app/javascript/packs/projects.js