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JavaScript and interaction · Lesson 13 / 14

Interfaces that explain waiting

An empty screen can mean waiting, no results or failure. People need to know which.

Learning paths16 min

Let's discover together

  1. 1

    Define states such as idle, loading, ready, empty and error. An empty list successfully received is not an error. Write a coherent message and action for each state.

  2. 2

    The workshop uses a status region and aria-busy on suggestions. Typed missions are separate from suggestions: loading failure should not erase a plan. Retry remains available.

  3. 3

    On a new request, increment a version and cancel the previous one. Before applying any result, check that its version is still current. This guard also helps when cancellation comes too late.

  4. 4

    The project ends a long wait with a message and allows retry. A timeout is an application choice, not a reliable measure of internet quality. Record scenarios, sequence and expected result in REVIEW.md.

From the example to your own interaction

Download this activity kit, extract it and open index.html in a browser. Edit lesson.js, save and reload. You do not need Node or packages. README explains local HTTP when needed.

The demonstration uses supplied JavaScript. It does not execute your editor code. Download your edit separately to test in the local kit.

My files and GitHub
Try the project we will build

Small mission planner

Create, complete and review a study plan using fictional data. Missions stay only in this page’s memory and disappear on reload.

Use a short title without personal data and whole minutes from 1 to 120. Up to 20 missions.

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    Suggestion lab

    Scenarios are simulated in this browser by default. No suggestion request is sent and your plan is not replaced.

    Available in the kit opened at http://127.0.0.1:8768. See README; no external account is needed.

      This JSON contains only missions, not your code. The demonstration does not import files or synchronize devices. Download edited JavaScript from the lesson file workspace.

      Official links and next step

      ✦
      YOUR MISSION

      Represent explicit states and prevent old responses from replacing current ones.

      Now it's your turn

      Discovery workshop

      Think before running

      Request A is slow. B starts later and returns an empty list first.
      Build your answers and check when you are ready.
      A moment to understand

      Should a suggestion failure erase typed missions?

      I need a hint

      Predict the result, run your file and explain the difference.

      Loading your journey…

      Take it with you

      Make a table of state, message and next action. Test empty, error and stale response; record that the typed plan stayed intact.

      At your own pace

      My files and GitHub

      Every lesson can become your own record: code, notes or a practice plan. Saving a file to GitHub is optional and does not change your XP.

      Student guide

      The editor and downloads open when this lesson is available to your account. Check access below or return to the track map.

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      Rullstpetbot

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