Power-up development: does .initialize run before cards are fully loaded?
Asked by Ernest Gazarian:

I am creating my first power-up for Trello, and I've run into a bit of a roadblock. The purpose of the power-up is very simple - to expose the state of all checklists on the back of a card in the form of a progress bar on the front of the card (using card-badges).

It very almost works, but not quite... When I load the board, all cards show the string "N/A", which is the fallback string when no checklist items are detected. The cards obviously have checklists though, as the in-built checklist card-badge works just fine, showing (3/7, or 2/14, or whatever the case may be). However, the moment I check or uncheck any item in a checklist, the progress bar appears on the front as expected.

My guess is that the .initialize method is being called before the cards are fully loaded, or something along those lines. As a first-timer here I expect I am probably just missing something extremely obvious... Can anyone point me in the right direction?

The code looks like this:

```
<!DOCTYPE html>
<html>
<head>
<title>Checklist Progress Power-Up</title>
<script src="https://p.trellocdn.com/power-up.min.js"></script>
</head>
<body>
<script>

function calculateChecklistProgress(card) {
let totalItems = 0;
let completedItems = 0;
if (card.checklists) {
card.checklists.forEach(function(checklist) {
if (checklist.checkItems) {
totalItems += checklist.checkItems.length;
completedItems += checklist.checkItems.filter(function(item) {
return item.state === 'complete';
}).length;
}
});
}

if (totalItems === 0) {
return 'N/A';
}

const progressPercentage = ((completedItems / totalItems) * 100).toFixed();

const progressBar = createProgressBar(progressPercentage);

return progressBar;
}

function createProgressBar(progressPercentage) {
const barLength = 10;
const completedChars = Math.round((progressPercentage / 100) * barLength);
const remainingChars = barLength - completedChars;

const progressBar = ' ? '.repeat(completedChars) + ' __ '.repeat(remainingChars)

return ` ${progressBar} ${progressPercentage}%`;
}

function updateCardBadges(t) {
return t.card('all')
.then(function(card) {
window.card = card;
const progress = calculateChecklistProgress(card);
return [{
text: progress,
color: 'light-gray',
}];
});
}

window.TrelloPowerUp.initialize({
'card-badges': function(t, options) {
return t.card('all')
.then(function(card) {
window.card = card;
return updateCardBadges(t);
});
},
});
</script>
</body>
</html>
```


Answers:
author: Oliver S
body: Hi Ernest, welcome to the community! :)

You've reached the Trello Community where users post general questions relating to using Trello and its features.

If it helps, you might be best to repost your question in the Trello Category on the Atlassian Developer Community: <https://community.developer.atlassian.com/c/trello/42>

You'll be more likely to get some eyes on it from others who are building Power-ups for Trello! :)

Hope this helps!

comments: author: Ernest Gazarian
body: Ooops, my mistake! Thanks for the tip!


author: Oliver S
body: No worries Ernest - all okay! Just didn't want your question to go unanswered for too long! :) Have a great week ahead!


Tags: checklist

power-up