00e797801d
* feat(imageLoader):Add an nth image loader strategy (#10) * Updates for PR for nth menu * performance:Prior implementation was O(n^2), taking about 50 ms * feat:Nth image loader, added docs as requested
45 lines
1.2 KiB
JavaScript
45 lines
1.2 KiB
JavaScript
/**
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* Returns a re-ordered array consisting of, in order:
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* 1. First few objects
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* 2. Center objects
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* 3. Last few objects
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* 4. nth Objects (n=7), set 2
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* 5. nth Objects set 5,
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* 6. Remaining objects
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* What this does is return the first/center/start objects, as those
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* are often used first, then a selection of objects scattered over the
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* instances in order to allow making requests over a set of image instances.
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*
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* @param {[]} imageIds
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* @returns [] reordered to be an nth selection
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*/
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export default function getNthFrames(imageIds) {
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const frames = [[], [], [], [], []];
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const centerStart = imageIds.length / 2 - 3;
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const centerEnd = centerStart + 6;
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for (let i = 0; i < imageIds.length; i++) {
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if (
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i < 2 ||
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i > imageIds.length - 4 ||
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(i > centerStart && i < centerEnd)
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) {
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frames[0].push(imageIds[i]);
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} else if (i % 7 === 2) {
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frames[1].push(imageIds[i]);
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} else if (i % 7 === 5) {
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frames[2].push(imageIds[i]);
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} else {
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frames[(i % 2) + 3].push(imageIds[i]);
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}
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}
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const ret = [
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...frames[0],
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...frames[1],
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...frames[2],
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...frames[3],
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...frames[4],
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];
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return ret;
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}
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