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    intersectionWith es-toolkit

    Returns a new array containing the intersection of two arrays based on a custom comparison function.

    const result = intersectionWith(firstArr, secondArr, areItemsEqual);

    Usage

    intersectionWith(firstArr, secondArr, areItemsEqual)

    Use intersectionWith when you want to find common elements in two arrays using a user-defined comparison function. This is useful for complex objects that are difficult to handle with simple value comparisons or when special comparison logic is needed.

    import { intersectionWith } from 'es-toolkit/array';

// Compare by object's id property
const users1 = [
  { id: 1, name: 'john' },
  { id: 2, name: 'jane' },
];
const users2 = [
  { id: 2, name: 'jane' },
  { id: 3, name: 'bob' },
];
intersectionWith(users1, users2, (a, b) => a.id === b.id);
// Returns: [{ id: 2, name: 'jane' }]

// Can also compare different types
const objects = [
  { id: 1, name: 'apple' },
  { id: 2, name: 'banana' },
];
const ids = [2, 3];
intersectionWith(objects, ids, (obj, id) => obj.id === id);
// Returns: [{ id: 2, name: 'banana' }]

    Complex comparison logic can also be implemented.

    import { intersectionWith } from 'es-toolkit/array';

// Case-insensitive string comparison
const words1 = ['Apple', 'Banana'];
const words2 = ['apple', 'cherry'];
intersectionWith(words1, words2, (a, b) => a.toLowerCase() === b.toLowerCase());
// Returns: ['Apple']

// Number comparison within a range
const numbers1 = [1.1, 2.3, 3.7];
const numbers2 = [1.0, 2.5, 4.0];
intersectionWith(numbers1, numbers2, (a, b) => Math.abs(a - b) < 0.5);
// Returns: [1.1, 2.3, 3.7] (all differ from the corresponding numbers by less than 0.5)

    Parameters

    firstArrreadonly T[]required

    The first array to compare.

    secondArrreadonly U[]required

    The second array to compare.

    areItemsEqual(x: T, y: U) => booleanrequired

    A function to determine if two elements are equal. Should return true if equal, false otherwise.

    Returns

    Returns a new array containing elements commonly included in both arrays based on the custom comparison function. The result consists of elements from the first array.

    T[]
    Source: es-toolkit

    Re-exported verbatim from es-toolkit. Implementation, edge cases, and performance behavior are owned upstream. This page mirrors the documentation at the pinned version; the linked source is authoritative.