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15 lines
684 B
JavaScript
15 lines
684 B
JavaScript
3 years ago
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"use strict";
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// TODO: Can probably be made more performant by precomputing a key -> item mapping, at the cost of multiple items with the same key becoming impossible
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module.exports = function diffLists(oldArray, newArray, keyFunction = (item) => item) {
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// NOTE: This only detects additions and removals, *not* order changes! The order is not relevant for our usecase.
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let oldSet = new Set(oldArray.map((item) => keyFunction(item)));
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let newSet = new Set(newArray.map((item) => keyFunction(item)));
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let removed = oldArray.filter((item) => !newSet.has(keyFunction(item)));
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let added = newArray.filter((item) => !oldSet.has(keyFunction(item)));
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return { removed, added };
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};
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