From 4ce99c998b6b77fce4b2590c17b921b3b76faa38 Mon Sep 17 00:00:00 2001
From: rizka10 <ristoe@hotmail.com>
Date: Thu, 3 Nov 2016 11:11:17 +0200
Subject: [PATCH] Improve summing poll percentages to 100
My first JavaScript! I have little experience with C++ and even less with Java, but that was enough to figure out a way to solve the task. The solution is rather good, but there may be better ways. I'm going to start a pull request. Even if it gets rejected, an expert can use the idea.
NOTE: The code needs some serious testing before potential merging. I did some testing and it worked, but don't trust in my skills.
---
.../assets/javascripts/lib/even-round.js.es6 | 28 +++++++++++++------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/plugins/poll/assets/javascripts/lib/even-round.js.es6 b/plugins/poll/assets/javascripts/lib/even-round.js.es6
index 0395f1f16a6..5446c874c58 100644
--- a/plugins/poll/assets/javascripts/lib/even-round.js.es6
+++ b/plugins/poll/assets/javascripts/lib/even-round.js.es6
@@ -1,17 +1,29 @@
-// stolen from http://stackoverflow.com/a/13484088/11983
+// works as described on http://stackoverflow.com/a/13483710
function sumsUpTo100(percentages) {
return percentages.map(p => Math.floor(p)).reduce((a, b) => a + b) === 100;
}
export default (percentages) => {
- const sumOfDecimals = Math.ceil(percentages.map(a => a % 1).reduce((a, b) => a + b));
- // compensate error by adding 1 to the first n "non-zero" items
- for (let i = 0, max = percentages.length; i < sumOfDecimals && i < max; i++) {
- if (percentages[i] > 0) {
- percentages[i] = ++percentages[i];
- // quit early when there is a rounding issue
- if (sumsUpTo100(percentages)) break;
+ var decimals = percentages.map(a => a % 1);
+ const sumOfDecimals = Math.ceil(decimals.reduce((a, b) => a + b));
+ // compensate error by adding 1 to n items with the greatest decimal part
+ for (let i = 0, max = decimals.length; i < sumOfDecimals && i < max; i++) {
+ // find the greatest item in the decimals array, set it to 0,
+ // and increase the corresponding item in the percentages array by 1
+ let greatest = 0;
+ let index = 0;
+ for (let j=0; j < decimals.length; j++) {
+ if (decimals[j] > greatest) {
+ index = j;
+ greatest = decimals[j];
+ }
}
+ ++percentages[index];
+ decimals[index] = 0;
+ // quit early when there is a rounding issue
+ if (sumsUpTo100(percentages)) break;
}
+
return percentages.map(p => Math.floor(p));
};
+