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Rachel Heneault
12,401 PointsJavascript for loops on data
After doing a rest api call, I have a list of data with 42 items. Each one has a date. Some dates are the same. I want to create a drop down based on the dates. But if I do this it shows all the dates. How do write the loop that will group the dates together and only show the a single date for each instance?
for (var i = 0;i < dat.length;i++){
html+='<option
value='+dat[i].highlight+'>'+dat[i].highlight+'</option>';
}
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2 Answers
Steven Parker
231,236 PointsIt looks like you only need unique dates, and don't need to maintain a correspondence with the original object(s). If so, you may be able to convert the dates to timestamps, pass them through a Set object (to insure uniqueness), and then convert them back. I haven't tried it, but I'm thinking it might look like this:
var uniqueDates = Array.from(new Set(dat.map(d => d.highlight.getTime())))
.map(t => new Date(t));
for (var d of uniqueDates) {
html += `<option value="${d}">${d}</option>`;
}
If you do need to maintain a correspondence, you'd probably need to create some extra processes, including a custom object comparison function.
Rachel Heneault
12,401 PointsThank you for your help.
When will the day exist when I don't get stumped or frustrated....
Steven Parker
231,236 PointsIf you never get stumped, it's time to find more challenging work! Tasks you can accomplish easily don't give you a chance to grow and will eventually become boring.
And there are always resources you can turn to. Sometimes perusing the documentation will do, otherwise you can seek advice from a co-worker, supervisor, or a forum like this one.
Enjoy working out the "puzzles", and happy coding!