Count items inside array of objects

Question

I am using this code to fetch 100 trending public repos on GitHub.

For every language, I calculated the The list of repos using the language, but I can't calculate the number of repos using this language

part of my code

const api_url =
    "https://api.github.com/search/repositories?q=created:>30&sort=stars&order=desc&per_page=100";
  const response = await fetch(api_url);
  const data = await response.json();

  var urls = data.items
      .map((a) => ({
        language: a.language,
        url: a.url,
      }))
      .filter((el) => {
        return el.language != null;
      }),
    result = urls.reduce((r, { language, url }) => {
      match = r.find((item) => language in item);
      match ? match[language].push(url) : r.push({ [language]: [url] });

      return r;
    }, []);

This is sample of my output

[{
"Vala": [
"https://api.github.com/repos/p-e-w/finalterm"
]},
{
"Swift": [
"https://api.github.com/repos/louisdh/panelkit",
"https://api.github.com/repos/hyperoslo/Whisper",
]},
{
"C": [
"https://api.github.com/repos/wishstudio/flinux",
"https://api.github.com/repos/Sunzxyong/Tiny"
]}]

My desired output is to count the URLs of each language and append it to its corresponding language

Add the count where? { "Vala": [ "https://api.github.com/repos/p-e-w/finalterm" ], count: 1}? You could just go through each language and get the .length of the array. — VLAZ
– VLAZ, Commented May 12, 2021 at 15:24

James · Accepted Answer · 2021-05-12 15:43:45Z

1

Some changes:

reduce urls to an object because it's faster to lookup entries than array.find and generally less complex.
take the object and generate an array with language, url list for that language, and count (which is just url list length).

const urls = [
  {language: "java", url: "url1"},
  {language: "java", url: "url2"},
  {language: "php", url: "url3"},
  {language: "javascript", url:"url4"},
  {language: "php", url: "url5"},
  {language: "java", url: "url6"}
];

result = Object.entries(
  urls.reduce((r, { language, url }) => {
    if (!r[language]) r[language] = [];
    r[language].push(url);
    return r;
  }, {})
).map(([language, urls]) => (
  {language, urls, count: urls.length}
));

console.log(result);

answered May 12, 2021 at 15:43

James

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1 Comment

Mohamed Khalifa Over a year ago

Thanks alot for your answer, it really helped me.

Pierre_T · Accepted Answer · 2021-05-12 15:34:31Z

0

Simplest approach would consist in changing your acc type from [] to {} that could carry a count property:

const urls = [{
  language: "Javascript",
  url: "url1"
}, {
  language: "Python",
  url: "url2"
}, {
  language: "Javascript",
  url: "url3"
}]

const result = urls.reduce((r, {
  language,
  url
}) => {
  if (r[language]) {
    r[language].urls.push(url)
    r[language].count ++

  } else {
    r[language] = { urls: [url], count : 1 }
  }
  
  return r;
}, {});

console.log(result)

Alternatively, to avoid looping 3 times on the items array, you could do all your operations from map et filter within the reduce

answered May 12, 2021 at 15:34

Pierre_T

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Comments

Lajos Arpad · Accepted Answer · 2021-05-12 15:45:36Z

0

This is how you can do it with map:

    console.log([{
    "Vala": [
    "https://api.github.com/repos/p-e-w/finalterm"
    ]},
    {
    "Swift": [
    "https://api.github.com/repos/louisdh/panelkit",
    "https://api.github.com/repos/hyperoslo/Whisper",
    ]},
    {
    "C": [
    "https://api.github.com/repos/wishstudio/flinux",
    "https://api.github.com/repos/Sunzxyong/Tiny"
    ]}].map((item) => {return {[Object.keys(item)[0]]: item[Object.keys(item)[0]].length}}));

answered May 12, 2021 at 15:45

Lajos Arpad

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Comments

Mister Jojo · Accepted Answer · 2021-05-12 16:06:56Z

0

simply do

let output = Object.entries( data.items.reduce((res,{url,language})=>
  {
  res[language] = res[language] ?? []
  res[language].push(url)
  return res
  },{})
).map(([k,v])=>({[k]:v, count: v.length}))

edited May 12, 2021 at 16:06

answered May 12, 2021 at 15:54

Mister Jojo

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