lodash._cacheindexof

// This package exposes an internal Lodash v3 function, `cacheIndexOf`. // It is typically not used directly by application developers but is leveraged by other Lodash modules // for performance optimization in operations like `_.uniq` or `_.intersection`. // Its purpose is to efficiently find the index of a value within an array, potentially using an auxiliary 'cache' array. // Installation: npm install lodash._cacheindexof const cacheIndexOf = require('lodash._cacheindexof'); function demonstrateCacheIndexOf() { const dataArray = ['apple', 'banana', 'orange', 'grape', 'banana']; const searchTerm1 = 'orange'; const searchTerm2 = 'grapefruit'; const searchTerm3 = 'banana'; // The 'cache' parameter is an internal array used by Lodash to track seen values // for performance optimization. When used directly, it can act as a simple auxiliary array. // In a full Lodash implementation, this might be a Set or another tracking mechanism. const internalCache = []; // Find an existing item let index = cacheIndexOf(dataArray, searchTerm1, internalCache); console.log(`'${searchTerm1}' found at index: ${index}`); // Expected: 2 // Find a non-existing item index = cacheIndexOf(dataArray, searchTerm2, internalCache); console.log(`'${searchTerm2}' found at index: ${index}`); // Expected: -1 // Find a duplicate item. Note: cacheIndexOf finds the *first* occurrence. index = cacheIndexOf(dataArray, searchTerm3, internalCache); console.log(`'${searchTerm3}' found at index: ${index}`); // Expected: 1 // The 'internalCache' array's modification by `cacheIndexOf` is context-dependent // within Lodash's full algorithms. For simple lookups as shown, it might remain unchanged. console.log(`State of internalCache after calls: ${JSON.stringify(internalCache)}`); } demonstrateCacheIndexOf();