@woosh/meep-engine/src/core/collection/array/array_contains_duplicates.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 * @template T
 * @param {T[]} source
 * @param {number} [start_index] first index to be included in the search
 * @param {number} [end_index] last index to be included in the search
 * @return {boolean}
 */
export function array_contains_duplicates(
    source,
    start_index = 0,
    end_index = source.length - 1
) {

    // going to n-1, as we check all elements forward from the current
    const last = end_index - 1;

    for (let k = start_index; k <= last; k++) {

        const element = source[k];

        // look for future occurrences of the same element
        if (source.indexOf(element, k + 1) !== -1) {
            return true;
        }

    }

    return false;
}