| 1234567891011121314151617181920 | 'use strict';const internals = {};module.exports = internals.flatten = function (array, target) {    const result = target || [];    for (let i = 0; i < array.length; ++i) {        if (Array.isArray(array[i])) {            internals.flatten(array[i], result);        }        else {            result.push(array[i]);        }    }    return result;};
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