{{alias}}( value[, level] )
    Copy or deep clone a value to an arbitrary depth.

    The implementation can handle circular references.

    If a `Number`, `String`, or `Boolean` object is encountered, the value is
    cloned as a primitive. This behavior is intentional.

    For objects, the implementation only copies enumerable keys and their
    associated property descriptors.

    The implementation only checks whether basic `Objects`, `Arrays`, and class
    instances are extensible, sealed, and/or frozen.

    Functions are not cloned; their reference is copied.

    The implementation supports custom error types which are `Error` instances
    (e.g., ES2015 subclasses).

    Support for copying class instances is inherently fragile. Any instances
    with privileged access to variables (e.g., within closures) cannot be
    cloned. This stated, basic copying of class instances is supported. Provided
    an environment which supports ES5, the implementation is greedy and performs
    a deep clone of any arbitrary class instance and its properties. The
    implementation assumes that the concept of `level` applies only to the class
    instance reference, but not to its internal state.

    Parameters
    ----------
    value: any
        Value to test.

    level: integer (optional)
         Copy depth. Default: Infinity.

    Returns
    -------
    out: any
        Value copy.

    Examples
    --------
    > var value = [ { 'a': 1, 'b': true, 'c': [ 1, 2, 3 ] } ];
    > var out = {{alias}}( value )
    [ { 'a': 1, 'b': true, 'c': [ 1, 2, 3 ] } ]
    > var bool = ( value[ 0 ].c === out[ 0 ].c )
    false

    // Set the `level` option to limit the copy depth:
    > value = [ { 'a': 1, 'b': true, 'c': [ 1, 2, 3 ] } ];
    > out = {{alias}}( value, 1 );
    > bool = ( value[ 0 ] === out[ 0 ] )
    true
    > bool = ( value[ 0 ].c === out[ 0 ].c )
    true


    See Also
    --------