numbers = ['99', '104']
repeat_twice = {
return function(str) {
return str.repeat(2);
}
}
function map(fn, array) {
return array.map(fn);
}
map(repeat_twice, numbers);
{
function unary(fn) {
return function(arg) {
return fn(arg);
}
}
const safer_parseint = unary(parseInt);
return map(safer_parseint, numbers);
}
function get_env() {
return fs.readFileSync('.env', 'utf-8');
}
function search_host(content) {
const exp = new RegExp('^HOST=');
const lines = content.split('\n');
return lines.find(line => exp.test(line));
}
function get_value(str) {
return str.split('=')[1];
}
get_value(search_host(get_env()));
test(ping(get_value(search_host(get_env()))));
function compose(...fns) {
return function _composed(...args) {
// Index of the last function
let last = fns.length - 1;
// Call the last function
// with arguments of `_composed`
let current_value = fns[last--](...args);
// loop through the rest in the opposite direction
for (let i = last; i >= 0; i--) {
current_value = fns[i](current_value);
}
return current_value;
};
}
{
const get_host = compose(get_value, search_host, get_env);
// get_host is `_composed`
return get_host();
}
{
const get_host = compose(
test,
ping,
get_value,
search_host,
get_env
);
return get_host();
}
function pipe(...fns) {
return function _piped(...args) {
// call the first function
// with the arguments of `_piped`
let current_value = fns[0](...args);
// loop through the rest in the original order
for (let i = 1; i < fns.length; i++) {
current_value = fns[i](current_value);
}
return current_value;
};
}
{
const get_host = pipe(get_env, search_host, get_value);
return get_host();
}
function cat(filepath) {
return fs.readFileSync(filepath, 'utf-8');
}
function grep(pattern, content) {
const exp = new RegExp(pattern);
const lines = content.split('\n');
return lines.find(line => exp.test(line));
}
function cut({ delimiter, fields }, str) {
return str.split(delimiter)[fields - 1];
}
cut({delimiter: '=', fields: 2}, grep('^HOST=', cat('.env')));
{
const get_host = pipe(
cat,
grep.bind(null, '^HOST='),
cut.bind(null, { delimiter: '=', fields: 2 })
);
return get_host('.env');
}
{
const get_host = pipe(
cat,
content => grep('^HOST=', content),
str => cut({ delimiter: '=', fields: 2 }, str)
);
return get_host('.env');
}
{
const add_one = num => num + 1;
const number = [41];
const empty = [];
return {
number: number.map(add_one).join(', '),
empty: empty.map(add_one).join(', ')
};
}
{
function cat(filepath) {
try {
return Result_v1.Ok(fs.readFileSync(filepath, 'utf-8'));
} catch(e) {
return Result_v1.Err(e);
}
}
return cat('.env');
}
{
function cat(filepath) {
try {
return Result_v1.Ok(fs.readFileSync(filepath, 'utf-8'));
} catch(e) {
return Result_v1.Err(e);
}
}
return cat('.env')
.map(grepp('^HOST='))
.map(cutt({ delimiter: '=', fields: 2 }));
}
{
const safer_cat = Result_v2.make_safe(cat);
return safer_cat('.env')
.map(grepp('^HOST='))
.map(cutt({ delimiter: '=', fields: 2 }))
}
{
const safer_cat = Result_v3.make_safe(cat);
const format_error = e => `Whoops: ${e.message}`;
return safer_cat('what?')
.map(grepp('^HOST='))
.map(cutt({ delimiter: '=', fields: 2 }))
.catchMap(format_error);
}
{
const constant = arg => () => arg;
const identity = arg => arg;
const safer_cat = Result_v4.make_safe(cat);
return safer_cat('what?')
.map(grepp('^HOST='))
.map(cutt({ delimiter: '=', fields: 2 }))
.cata(constant("This ain't right"), identity)
}
{
const maybe_host = Maybe_v1.wrap_fun(grepp('^HOST='));
return maybe_host(cat('.env'))
.catchMap(() => 'Nothing()')
.cata(identity, identity);
}
safer_cat('.env')
.map(maybe_host)
.cata(identity, identity);
maybe_host = Maybe_v2.wrap_fun(grepp('^HOST='));
safer_cat('.env')
.flatMap(maybe_host)
.catchMap(() => 'what?')
.cata(identity, identity);
{
const safer_cat = Result_v5.make_safe(cat);
const maybe_host = Maybe_v2.wrap_fun(grepp('^HOST='));
const get_value = Maybe_v2.wrap_fun(cutt({delimiter: '=', fields: 2}));
const host = safer_cat('.env')
.flatMap(maybe_host)
.flatMap(get_value)
.cata(
constant('http://127.0.0.1:3000'),
identity
);
return host;
}
{
const chain = fn => m => m.flatMap(fn);
const unwrap_or = fallback => fm =>
fm.cata(constant(fallback), identity);
const safer_cat = Result_v5.make_safe(cat);
const maybe_host = Maybe_v2.wrap_fun(grepp('^HOST='));
const get_value = Maybe_v2.wrap_fun(cutt({delimiter: '=', fields: 2}));
const get_host = pipe(
safer_cat,
chain(maybe_host),
chain(get_value),
unwrap_or('http://127.0.0.1:3000')
);
return get_host('.env');
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
