0.8
a collection of usefull functions
Repository
Current version released
11 months ago
Handy Helpers
this is a collection of useful functions
f_move_in_array
moves a value in an array, it does not swap the elements!
let a_n = [2,0,1,0,0]
f_move_in_array(a_n, 2, 0)
f_assert_equals(
JSON.stringify(a_n),
`[1,2,0,0,0]`
)
f_move_in_array(a_n, 1, a_n.length-1)
f_assert_equals(
JSON.stringify(a_n),
`[1,0,0,0,2]`
)
f_move_in_array(a_n, 2, a_n.length-1)
f_assert_equals(
JSON.stringify(a_n),
`[1,0,0,2,0]`
)
f_move_in_array(a_n, 0, -1)
f_assert_equals(
JSON.stringify(a_n),
`[0,0,2,0,1]`
)
f_move_in_array(a_n, -1, 0)
f_assert_equals(
JSON.stringify(a_n),
`[1,0,0,2,0]`
)
let o1 = {n:1}
let o2 = {n:2}
let o3 = {n:3}
let o4 = {n:4}
let o5 = {n:5}
let a_o = [o1,o2,o3,o4,o5];
var n_idx_from = 0;
var n_idx_to = 2;
var o_from = a_o[n_idx_from];
var o_to = a_o[n_idx_to];
f_move_in_array(a_o, n_idx_from, n_idx_to)
f_assert_equals(
a_o[n_idx_to],
o_from
)
f_swap_in_array
swaps two values in an array
let a_n = [2,0,1,0,0]
f_swap_in_array(a_n, 2, 0)
f_assert_equals(
JSON.stringify(a_n),
`[1,0,2,0,0]`
)
f_swap_in_array(a_n, 0, a_n.length-1)
f_assert_equals(
JSON.stringify(a_n),
`[0,0,2,0,1]`
)
f_swap_in_array(a_n, 2, a_n.length-1)
f_assert_equals(
JSON.stringify(a_n),
`[0,0,1,0,2]`
)
f_swap_in_array(a_n, -1, 2)
f_assert_equals(
JSON.stringify(a_n),
`[0,0,2,0,1]`
)
f_swap_in_array(a_n, 2, -1)
f_assert_equals(
JSON.stringify(a_n),
`[0,0,1,0,2]`
)
f_move_v_in_array
moves a value in an array by a index difference
let a_s = ["a","b","c","d"];
f_move_v_in_array(a_s, "a", 2)
f_assert_equals(
JSON.stringify(a_s),
'["b","c","a","d"]'
)
f_move_v_in_array(a_s, "d", -3)
f_assert_equals(
JSON.stringify(a_s),
'["d","b","c","a"]'
)
let o1 = {n:1}
let o2 = {n:2}
let o3 = {n:3}
let o4 = {n:4}
let o5 = {n:5}
let a_o = [o1,o2,o3,o4,o5];
f_move_v_in_array(a_o, o1, -1)
f_assert_equals(
a_o.at(-1) == o1,
true
)
f_swap_v_in_array
moves a value in an array by a index difference
let a_s = ["a","b","c","d"];
f_swap_v_in_array(a_s, "a", "d")
f_assert_equals(
JSON.stringify(a_s),
'["d","b","c","a"]'
)
f_swap_v_in_array(a_s, "b", "c")
f_assert_equals(
JSON.stringify(a_s),
'["d","c","b","a"]'
)
let o1 = {n:1}
let o2 = {n:2}
let o3 = {n:3}
let o4 = {n:4}
let o5 = {n:5}
let a_o = [o1,o2,o3,o4,o5];
f_swap_v_in_array(a_o, o1, o5)
f_assert_equals(
a_o.at(-1) == o1,
true
)
f_assert_equals(
a_o.at(0) == o5,
true
)f_sleep_ms
let n_ms = window.performance.now();
await f_sleep_ms(333);
f_assert_equals(
(window.performance.now() - n_ms) >= 333,
true
)Handy snippets
extend a file name by ‘_thumb’
// extend the prototype
f_assert_equals(
'some_image.png'
.split('.')
.map((v, n_idx, a)=>{
return (n_idx == a.length-2) ? `${v}_thumb`: v
})
.join('.'),
'some_image_thumb.png'
)
f_o_resp__fetch_cached
makes a fetch but caches the response meta (status, statusText, headers) and data as a_n_u8
var o_resp = await f_o_resp__fetch_cached(
fetch, // f_fetch
[ // a_v_arg__for_f_fetch
'https://deno.com/',
{'headers': {'User-Agent': "Test 1.2/3"}}
],
true,// b_overwrite_cached_file
1000, // n_ms_diff__overwrite_cached_file
async (
s_url
)=>{ // f_s_name_file_cached
// available functions
// f_s_name_file_cached__base64encoded -> 'aHR0cHM6Ly9kZW5vLmNvbS8='
// f_s_name_file_cached__hashed -> 'd2a68e83cffd1f8dc53143c95006f862f199082b'
// f_s_name_file_cached__readable_ignore_fragment_and_getparams -> 'https______deno__com'
return `${s_url.split('?').shift().replaceAll('/', '--').replaceAll(':', '__')}}`
},
'./.cache'//a custom path to a folder for the cache
);
f_assert_equals(
o_resp?.b_from_disk,
undefined
);f_b_deno
check if script is running with https://deno.com/
f_assert_equals(f_b_denojs(), ("Deno" in window))f_o_html_element__from_s_tag
returns a html element browser: document.createElement denojs: using /x/deno_dom
f_assert_equals((await f_o_html_element__from_s_tag('h1')).tagName, 'H1');f_o_html__from_s_html
returns a html element browser: div.innerHTML = s_html denojs: using /x/deno_dom
f_assert_equals(
(await f_o_html__from_s_html('<div><h1>hello</h1><h1>world</h1></div>')).querySelectorAll('h1')[1].innerText,
'world'
);f_download_file__from_s_url
download a file, pass an optional callback, or let log the download state by default
await f_download_file__from_s_url(
// 'https://www.dwsamplefiles.com/?dl_id=409'
// 'https://images.unsplash.com/photo-1533144188434-eb0442504392?auto=format&fit=crop&q=80&w=3948&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D',
// 'a_picture_in_bird_perspective.png'
'https://www.w3schools.com/html/pic_trulli.jpg',
'./.gitignored/lol/test.jpg'//if denojs we can pass a path
)
f_a_n_u8__from_s_url_with_download_speed_easy
get the response body as Uint8array (a_n_u8) from an url, while the download is pending a callback will be executed every nth millisecond in this callback one can print download speed, if the response header ‘content-length’ is present and its value is legit one can also print the download percentage
let a_n_u8 = await f_a_n_u8__from_s_url_with_download_speed_easy(
'https://www.dwsamplefiles.com/?dl_id=406',
function(
n_mb_downloaded,
n_mb_per_sec_domwnload_speed,
n_mb_to_download_total
){
let s_from_total = ''
if(n_mb_to_download_total != -1){
s_from_total = (`/${(n_mb_to_download_total).toFixed(0)}`)
}
console.log(`downloaded ${(n_mb_downloaded).toFixed(0)}${s_from_total}(MB) @ ${n_mb_per_sec_domwnload_speed.toFixed(2)} MB/s`)
},
555// callback gets called every 555 milliseconds
)
f_assert_equals(a_n_u8.length, 15944874)
Overwrite / ‘Monkey-Patch’ the fetch function
replace the original fetch function, with a custom fetch function, for example to change some headers
this can be used in combination with f_o_resp__fetch_cached, f_download_file__from_s_url
let f_fetch_original = window.fetch
window.fetch = async function(){
let a_v_arg = Array.from(arguments);
let s_url = a_v_arg?.[0];
if(s_url?.includes('httbin_non_existing_lol.org')){
a_v_arg[0] = s_url.replace('httbin_non_existing_lol.org', 'httpbin.org')
}
// we can cache some sites
if(s_url == 'https://httpbin.org/status/418'){
return f_o_resp__fetch_cached(
f_fetch_original,
a_v_arg
);
}
// we could ignore the patching on some fetch calls
if(s_url.includes('#dont_monkey_patch')){
return f_fetch_original(...a_v_arg)
}
return f_fetch_original(
a_v_arg[0],
{
headers: {
'User-Agent': [
`Gozilla/${(Math.random()*5+1).toFixed(1)}`,
`(Dingos TN 2.1; Din64; x128; rv:27.0)`,
`Lizzard/20100101 Waterwhale/42.0`
].join(' ')
}
}
)
}
var o_data = await (await fetch('https://httpbin.org/headers')).json();
f_assert_equals(o_data.headers['User-Agent'].includes('Gozilla/'),true)
var o_data = await (await fetch('https://httbin_non_existing_lol.org/headers')).json();
f_assert_equals(o_data.headers['User-Agent'].includes('Gozilla/'),true)
var o_data = await (await fetch('https://httpbin.org/headers#dont_monkey_patch')).json();
f_assert_equals(o_data.headers['User-Agent'].includes('Deno/'),true)
var o_data = await fetch('https://httpbin.org/status/418');
var o_data = await fetch('https://httpbin.org/status/418');
f_assert_equals(o_data.b_from_disk, true)
// restore the original function
window.fetch = f_fetch_original
// test the restored function
var o_data = await (await fetch('https://httpbin.org/headers')).json();
f_assert_equals(
o_data.headers['User-Agent'].includes('Deno/'),
true
)
f_o_html__from_s_url
a handy function to directly get a js object html document from a url, works in deno and browser
let o_doc = (await f_o_html__from_s_url(
`https://deno.land`
))
f_assert_equals(
typeof o_doc.body.querySelectorAll,
'function'
)
f_s_hashed
hash a string, using the window.crypto.subtle API, available functions at the moment are ‘sha-1’, ‘sha-256’, ‘sha-384’, ‘sha-512’
f_assert_equals(
await f_s_hashed('lol this is a text', 'SHA-1'),
'd2a68e83cffd1f8dc53143c95006f862f199082b'
)