baseline-polyfill.js

if (typeof Object.assign != 'function') {
	// from MDN
	Object.assign = function(target, varArgs) { // .length of function is 2
		'use strict';
		if (target == null) { // TypeError if undefined or null
			throw new TypeError('Cannot convert undefined or null to object');
		}

		var to = Object(target);

		for (var index = 1; index < arguments.length; index++) {
			var nextSource = arguments[index];

			if (nextSource != null) { // Skip over if undefined or null
				for (var nextKey in nextSource) {
					// Avoid bugs when hasOwnProperty is shadowed
					if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
						to[nextKey] = nextSource[nextKey];
					}
				}
			}
		}
		return to;
	};
}

Function.flow = function() {
	var fs = [].slice.call( arguments );
	return fs.reduce( function( acc, f ) {
		if ( ! acc ) return f;
		return function() {
			return f( acc.apply( this, arguments ) );
		};
	} );
};

[ 'map', 'filter', 'reduce', 'some', 'every' ].forEach( function ( key ) {
	if ( ! Array.prototype[ key ] ) return;
	Function[ key ] = function( a, b ) {
		return function( xs ) {
			return xs[ key ]( a, b );
		};
	};
} );

Function.flatten = function( xs ) {
	return xs.reduce( function( acc, x ) {
		return acc.concat( x );
	}, [] );
};

Function.flatMap = function( f ) {
	return Function.flow( Function.map( f ), Function.flatten );
};