63 lines
1.4 KiB
JavaScript
63 lines
1.4 KiB
JavaScript
'use strict';
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const array = require('./array.cjs');
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const series = (items, toKey = (item) => `${item}`) => {
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const { indexesByKey, itemsByIndex } = items.reduce(
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(acc, item, idx) => ({
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indexesByKey: {
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...acc.indexesByKey,
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[toKey(item)]: idx
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},
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itemsByIndex: {
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...acc.itemsByIndex,
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[idx]: item
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}
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}),
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{
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indexesByKey: {},
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itemsByIndex: {}
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}
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);
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const min = (a, b) => {
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return indexesByKey[toKey(a)] < indexesByKey[toKey(b)] ? a : b;
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};
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const max = (a, b) => {
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return indexesByKey[toKey(a)] > indexesByKey[toKey(b)] ? a : b;
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};
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const first = () => {
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return itemsByIndex[0];
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};
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const last = () => {
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return itemsByIndex[items.length - 1];
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};
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const next = (current, defaultValue) => {
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return itemsByIndex[indexesByKey[toKey(current)] + 1] ?? defaultValue ?? first();
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};
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const previous = (current, defaultValue) => {
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return itemsByIndex[indexesByKey[toKey(current)] - 1] ?? defaultValue ?? last();
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};
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const spin = (current, num) => {
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if (num === 0)
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return current;
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const abs = Math.abs(num);
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const rel = abs > items.length ? abs % items.length : abs;
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return array.list(0, rel - 1).reduce(
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(acc) => num > 0 ? next(acc) : previous(acc),
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current
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);
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};
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return {
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min,
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max,
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first,
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last,
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next,
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previous,
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spin
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};
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};
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exports.series = series;
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//# sourceMappingURL=series.cjs.map
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