study-overview/src/util/clone.js

a high-level summary of study accrual and data cleaning metrics

export default function clone(obj) {
    let copy;

    // Handle the 3 simple types, and null or undefined
    if (null == obj || 'object' != typeof obj) return obj;

    // Handle Date
    if (obj instanceof Date) {
        copy = new Date();
        copy.setTime(obj.getTime());

        return copy;
    }

    // Handle Array
    if (obj instanceof Array) {
        copy = [];

        for (let i = 0, len = obj.length; i < len; i++) {
            copy[i] = clone(obj[i]);
        }

        return copy;
    }

    // Handle Object
    if (obj instanceof Object) {
        copy = {};

        for (const attr in obj) {
            if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);
        }

        return copy;
    }

    throw new Error("Unable to copy obj! Its type isn't supported.");
}