I have a piece of code that looks like:
const desktop = platform.filter(el => el == "desktop").length;
const mobile = platform.filter(el => el == "mobile").length;
const android = platform.filter(el => el == "android").length;
and so on..
Basically I have an array that contains multiple entries of those strings and I want to collect the length of each property in a variable. The above works but I was wondering if there is a cleaner way to avoid filter through the array multiple times?
You can use a single reduce to count the number of appearances of the items:
const platform = ['desktop', 'other', 'mobile', '', 'other', 'android', 'android'];
const { desktop, mobile, android } = platform.reduce((r, el) => {
if (el in r) r[el]++;
return r;
}, { desktop: 0, mobile: 0, android: 0 });
console.log({ desktop, mobile, android });While it would not avoid the multiple iterations, you could write an equivalent more cleanly:
const desktop = platform .includes ("desktop")
const mobile = platform .includes ("mobile")
const android = platform .includes ("android")
But if the multiple iterations are a real problem, Ori Drori's technique should cover it.
Use reduce and build one generic object.
const platforms = ['desktop', 'android', 'desktop', 'android', 'mobile'];
const len = platforms.reduce(
(acc, item) =>
Object.assign(acc, { [item]: item in acc ? acc[item] + 1 : 1 }),
{}
);
console.log(len['desktop'], len.mobile)