function factory() {
	var config;
	var pool;
	var conf;
	var rand;
	var err;
	var fcn;

	conf = copy( defaults );
	if ( arguments.length === 1 ) {
		if ( isArrayLike( arguments[ 0 ] ) || isTypedArrayLike( arguments[ 0 ] ) ) { // eslint-disable-line max-len
			pool = arguments[ 0 ];
		} else {
			config = arguments[ 0 ];
			err = validate( conf, config );
		}
	} else if ( arguments.length > 1 ) {
		pool = arguments[ 0 ];
		config = arguments[ 1 ];
		if ( !( isArrayLike( pool ) || isTypedArrayLike( pool ) ) ) {
			throw new TypeError( format( 'invalid argument. `%s` argument must be array-like. Value: `%s`.', 'pool', pool ) );
		}
		err = validate( conf, config );
	}
	if ( err ) {
		throw err;
	}
	if ( config && config.seed ) {
		rand = randu({
			'seed': config.seed
		});
	} else {
		rand = randu();
	}
	if ( pool === void 0 ) {
		fcn = sample1;
	} else {
		if ( isString( pool ) ) {
			pool = pool.split( '' );
		} else {
			pool = copy( pool );
		}
		fcn = sample2;
	}
	setReadOnly( fcn, 'seed', rand.seed );
	setReadOnly( fcn, 'PRNG', rand );

	rand = rand.normalized;

	return fcn;

	/**
	* Samples elements from an array-like object.
	*
	* @private
	* @param {(ArrayLike|TypedArrayLike)} x - array-like object from which to sample elements
	* @param {Options} [options] - function options
	* @param {NonNegativeInteger} [options.size] - sample size
	* @param {ProbabilityArray} [options.probs] - element probabilities
	* @param {boolean} [options.replace=true] - boolean indicating whether to sample with replacement
	* @throws {TypeError} first argument must be array-like
	* @throws {TypeError} options argument must be an object
	* @throws {TypeError} must provide valid options
	* @throws {RangeError} `size` option must be less than or equal to the length of `x` when the `replace` option is `false`
	* @returns {Array} sample
	*/
	function sample1( x, options ) {
		var replace;
		var xcopy;
		var probs;
		var opts;
		var size;
		var err;

		if ( !( isArrayLike( x ) || isTypedArrayLike( x ) ) ) {
			throw new TypeError( format( 'invalid argument. First argument must be array-like. Value: `%s`.', x ) );
		}
		if ( isString( x ) ) {
			x = x.split( '' );
		}
		opts = {};
		if ( arguments.length > 1 ) {
			err = validate( opts, options );
			if ( err ) {
				throw err;
			}
		}
		if ( opts.replace === void 0 ) {
			replace = conf.replace;
		} else {
			replace = opts.replace;
		}
		if ( opts.probs !== void 0 ) {
			probs = opts.probs;
		}
		if ( opts.size ) {
			size = opts.size;
		} else if ( conf.size ) {
			size = conf.size;
		} else {
			size = x.length;
		}
		if (
			replace === false &&
			size > x.length
		) {
			throw new RangeError( format( 'invalid option. `size` option must be less than or equal to the length of `x` when `replace` is `false`. Option: `%s`.', size ) );
		}
		// Custom probabilities...
		if ( probs ) {
			if ( replace ) {
				return vose( x, size, rand, probs );
			}
			return renormalizing( x, size, rand, probs );
		}
		// All elements equally likely...
		if ( replace ) {
			return discreteUniform( x, size, rand );
		}
		xcopy = slice.call( x );
		return fisherYates( xcopy, size, rand );
	}

	/**
	* Samples elements from a population.
	*
	* @private
	* @param {Options} [options] - function options
	* @param {NonNegativeInteger} [options.size] - sample size
	* @param {boolean} [options.replace=true] - boolean indicating whether to sample with replacement
	* @param {boolean} [options.mutate=false] - boolean indicating whether to mutate the `pool` when sampling without replacement
	* @throws {TypeError} options argument must be an object
	* @throws {TypeError} must provide valid options
	* @throws {RangeError} `size` option must be less than or equal to the population when the `replace` option is `false`
	* @returns {Array} sample
	*/
	function sample2( options ) {
		var replace;
		var mutate;
		var opts;
		var size;
		var err;
		var out;

		if ( pool.length === 0 ) {
			return null;
		}
		opts = {};
		if ( arguments.length ) {
			err = validate( opts, options );
			if ( err ) {
				throw err;
			}
		}
		if ( opts.mutate === void 0 ) {
			mutate = conf.mutate;
		} else {
			mutate = opts.mutate;
		}
		if ( opts.replace === void 0 ) {
			replace = conf.replace;
		} else {
			replace = opts.replace;
		}
		if ( opts.size ) {
			size = opts.size;
		} else if ( conf.size ) {
			size = conf.size;
		} else {
			size = pool.length;
		}
		if (
			replace === false &&
			size > pool.length
		) {
			throw new RangeError( format( 'invalid option. `size` option must be less than or equal to the population size when `replace` is `false`. Option: `%s`.', size ) );
		}
		if ( replace ) {
			return discreteUniform( pool, size, rand );
		}
		out = fisherYates( pool, size, rand );
		if ( mutate ) {
			// Remove the sample observations:
			pool = pool.slice( size, pool.length );
		}
		return out;
	}
}
Returns a function to sample elements from an array-like object.

@param {(ArrayLike|TypedArrayLike)} [pool] - array-like object from which to sample
@param {Options} [options] - function options
@param {PositiveInteger} [options.seed] - integer-valued seed
@param {NonNegativeInteger} [options.size] - sample size
@param {boolean} [options.replace=true] - boolean indicating whether to sample with replacement
@param {boolean} [options.mutate=false] - boolean indicating whether to mutate the `pool` when sampling without replacement
@throws {TypeError} `pool` must be an array-like object
@throws {TypeError} options argument must be an object
@throws {TypeError} must provide valid options
@returns {Function} function to sample elements from an array-like object

@example
var sample = factory({
    'seed': 232
});
var out = sample( 'abcdefg' );
// e.g., returns [ 'g', 'd', 'g', 'f', 'c', 'e', 'f' ]

@example
var sample = factory( [ 1, 2, 3, 4, 5, 6 ], {
    'seed': 232,
    'size': 2
});
var out = sample();
// e.g., returns [ 6, 4 ]

out = sample();
// e.g., returns [ 6, 5 ]

@example
var sample = factory( [ 1, 2, 3, 4, 5, 6 ], {
    'seed': 474,
    'size': 3,
    'mutate': true,
    'replace': false
});
var out = sample();
// e.g., returns [ 4, 3, 6 ]

out = sample();
// e.g., returns [ 1, 5, 2 ]

out = sample();
// returns null

@example
var sample = factory( [ 0, 1 ], {
    'size': 2
});

var out = sample();
// e.g., returns [ 1, 1 ]

out = sample({
    'size': 10
});
// e.g., returns [ 0, 1, 1, 1, 0, 1, 0, 0, 1, 1 ]

@example
var sample = factory( [ 0, 1 ], {
    'size': 2
});

var out = sample();
// e.g., returns [ 1, 1 ]

out = sample({
    'replace': false
});
// e.g., returns [ 0, 1 ] or [ 1, 0 ]

out = sample();
// e.g., returns [ 1, 1 ]

@example
var sample = factory( [ 0, 1 ], {
    'size': 2,
    'mutate': true
});

var out = sample();
// e.g., returns [ 1, 1 ]

out = sample({
    'replace': false
});
// e.g., returns [ 0, 1 ] or [ 1, 0 ]

out = sample();
// returns null