40 lines
1.2 KiB
JavaScript
40 lines
1.2 KiB
JavaScript
export function findExpandedKeys() {
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let prev = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : [];
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let next = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
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const prevLen = prev.length;
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const nextLen = next.length;
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if (Math.abs(prevLen - nextLen) !== 1) {
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return {
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add: false,
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key: null
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};
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}
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function find(shorter, longer) {
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const cache = new Map();
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shorter.forEach(key => {
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cache.set(key, true);
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});
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const keys = longer.filter(key => !cache.has(key));
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return keys.length === 1 ? keys[0] : null;
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}
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if (prevLen < nextLen) {
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return {
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add: true,
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key: find(prev, next)
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};
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}
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return {
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add: false,
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key: find(next, prev)
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};
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}
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export function getExpandRange(shorter, longer, key) {
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const shorterStartIndex = shorter.findIndex(item => item.key === key);
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const shorterEndNode = shorter[shorterStartIndex + 1];
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const longerStartIndex = longer.findIndex(item => item.key === key);
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if (shorterEndNode) {
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const longerEndIndex = longer.findIndex(item => item.key === shorterEndNode.key);
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return longer.slice(longerStartIndex + 1, longerEndIndex);
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}
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return longer.slice(longerStartIndex + 1);
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} |