function inmap( collection, fcn, thisArg ) {
	var len;
	var v;
	var i;
	if ( !isCollection( collection ) ) {
		throw new TypeError( format( 'invalid argument. First argument must be a collection. Value: `%s`.', collection ) );
	}
	if ( !isFunction( fcn ) ) {
		throw new TypeError( format( 'invalid argument. Second argument must be a function. Value: `%s`.', fcn ) );
	}
	len = collection.length;
	for ( i = 0; i < len; i++ ) {
		v = fcn.call( thisArg, collection[ i ], i, collection );

		// Account for dynamically resizing a collection...
		if ( len !== collection.length ) {
			len = collection.length;
		}
		if ( i < len ) {
			collection[ i ] = v;
		}
	}
	return collection;
}
Invokes a function once for each element in a collection and updates the collection in-place.

## Notes

-   The invoked function's return value is cached prior to updating a collection. Before updating the collection, a collection must be inspected to ensure that a collection has not been resized during invocation such that an index no longer has a corresponding element in the collection. Were a return value automatically used to update a collection, an input collection could be converted into a sparse data structure. While some might consider this a feature, here, we take stance that a user should be less clever.

@param {Collection} collection - input collection
@param {Function} fcn - function to invoke
@param {*} [thisArg] - execution context
@throws {TypeError} first argument must be a collection
@throws {TypeError} second argument must be a function
@returns {Collection} input collection

@example
function scale( value, index, collection ) {
    return value * index;
}

var arr = [ 1, 2, 3, 4 ];

var out = inmap( arr, scale );
// returns [ 0, 2, 6, 12 ]

var bool = ( out === arr );
// returns true