Code for "Transforming Composition" talk

01.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

var movieListings = [];

for (let movieID of movieIDs) {
	if (validMovie(movieID)) {
		let movieData = lookupMovie(movieID);
		if (recentMovie(movieData)) {
			movieListings.push(
				formatMovie(movieData)
			);
		}
	}
}

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]

// *******************************

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

02.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

var movieListings = (
	movieIDs
		.filter(validMovie)
		.map(lookupMovie)
		.filter(recentMovie)
		.map(formatMovie)
);

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]

// *******************************

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

03.js

var mockData = getMockData(); // mock API response data

formatMovie(lookupMovie(699));	// "How To Train Your Dragon (2010)"

var dragon1 = compose(formatMovie,lookupMovie);
dragon1(699);					// "How To Train Your Dragon (2010)"

var dragon2 = flow(lookupMovie,formatMovie);
dragon2(699);					// "How To Train Your Dragon (2010)"


// *******************************

// aka: compose-right
function compose(...fns) {
	return v => fns.reduceRight((inp,fn) => fn(inp),v);
}
// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

04.js

var mockData = getMockData(); // mock API response data

formatMovie(recentMovie(lookupMovie(699)));	// "undefined (undefined)"

var dragon1 = compose(formatMovie,recentMovie,lookupMovie);
dragon1(699);					// "undefined (undefined)"

var dragon2 = flow(lookupMovie,recentMovie,formatMovie);
dragon2(699);					// "undefined (undefined)"


// *******************************

// aka: compose-right
function compose(...fns) {
	return v => fns.reduceRight((inp,fn) => fn(inp),v);
}
// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How to Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

05.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

function showMovie(movieID) {
	if (validMovie(movieID)) {
		var movieData = lookupMovie(movieID);
		if (recentMovie(movieData)) {
			return formatMovie(movieData);
		}
	}
}
showMovie(699);	// "How to Train Your Dragon (2010)"

movieIDs
	.map(showMovie)
	.filter(Boolean);	// remove pesky undefineds
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]


// *******************************

// aka: compose-right
function compose(...fns) {
	return v => fns.reduceRight((inp,fn) => fn(inp),v);
}
// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) { return `${movieData.title} (${movieData.released})`; }

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

06.js

var mockData = getMockData(); // mock API response data

var showMovie = flow(
	filter(validMovie),
	map(lookupMovie),
	filter(recentMovie),
	map(formatMovie)
);

showMovie([ 699 ]).next();
// { value: "How To Train Your Dragon (2010)", done: false }


// *******************************

function filter(fn) {
	return function *filter(iterable) {
		for (let v of iterable) {
			if (fn(v)) {
				yield v;
			}
		}
	};
}

function map(fn) {
	return function *map(iterable) {
		for (let v of iterable) {
			yield fn(v);
		}
	};
}

// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) { return `${movieData.title} (${movieData.released})`; }

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

07.js

var mockData = getMockData(); // mock API response data

var showMovie = flow(
	gather,
	filter(validMovie),
	map(lookupMovie),
	filter(recentMovie),
	map(formatMovie),
	takeOne
);

showMovie(699);	// "How To Train Your Dragon (2010)"


// *******************************

function filter(fn) {
	return function *filter(iterable) {
		for (let v of iterable) {
			if (fn(v)) {
				yield v;
			}
		}
	};
}

function map(fn) {
	return function *map(iterable) {
		for (let v of iterable) {
			yield fn(v);
		}
	};
}

function gather(...vals) { return vals; }

function takeOne(iter) { return iter.next().value; }

// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

08.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

var movieListings = (
	flow(
		filter(validMovie),
		map(lookupMovie),
		filter(recentMovie),
		map(formatMovie),
		takeAll
	)(movieIDs)
);

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]


// *******************************

function filter(fn) {
	return function *filter(iterable) {
		for (let v of iterable) {
			if (fn(v)) {
				yield v;
			}
		}
	};
}

function map(fn) {
	return function *map(iterable) {
		for (let v of iterable) {
			yield fn(v);
		}
	};
}

function takeAll(iter) { return [ ...iter ]; }

// aka: compose-left
function flow(...fns) {
	return v => fns.reduce((inp,fn) => fn(inp),v);
}

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

09.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

var movieListings = (
	Iterator.from(movieIDs)
		.filter(validMovie)
		.map(lookupMovie)
		.filter(recentMovie)
		.map(formatMovie)
		.toArray()
);

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]


// *******************************

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

10.js

var mapT =
	mapperFn =>
		combinerFn =>
			(list,v) =>
				combinerFn(list,mapperFn(v));
var filterT =
	predicateFn =>
		combinerFn =>
			(list,v) =>
				predicateFn(v) ? combinerFn(list,v) : list;
var transduceL =
	fn =>
		list =>
			list.reduce(fn(concatL),[]);
function concatL(list,v) { return list.concat(v); }

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

var movieListings = (
	transduceL(
		compose(
			filterT(validMovie),
			mapT(lookupMovie),
			filterT(recentMovie),
			mapT(formatMovie)
		)
	)(movieIDs)
);

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]


// *******************************


// aka: compose-right
function compose(...fns) {
	return v => fns.reduceRight((inp,fn) => fn(inp),v);
}

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}

11.js

var mockData = getMockData(); // mock API response data
var movieIDs = [ 627, 699, 378, 92, 933, 725, 528, 3, 156, ];

import { serial as FaS, transducers as FaT } from "fasy";

var movieListings = await (
	FaT.into(
		FaS.compose([
			FaT.filter(validMovie),
			FaT.map(lookupMovie),
			FaT.filter(recentMovie),
			FaT.map(formatMovie)
		]),
		[],
		movieIDs
	)
);

console.log(movieListings);
// [ "How To Train Your Dragon (2010)", "Barbie (2023)", "Frozen (2013)" ]

// *******************************

function validMovie(movieID) { return movieID >= 100; }
function recentMovie(movieData) { return movieData.released >= 2000; };
function formatMovie(movieData) {
	return `${movieData.title} (${movieData.released})`;
}

// mock of fetching movie from an external database
async function lookupMovie(movieID) { return mockData[movieID]; }
function getMockData() {
	return {
		156: { title: "Gone With The Wind", released: 1940, },
		378: { title: "The Godfather", released: 1972, },
		528: { title: "Star Wars: A New Hope", released: 1977, },
		627: { title: "Titanic", released: 1997, },
		699: { title: "How To Train Your Dragon", released: 2010, },
		725: { title: "Frozen", released: 2013, },
		933: { title: "Barbie", released: 2023, },
	};
}