10 crazy oneliners in javascript

[1, 2, 3].reduce((a, b) => a + b) - This line uses the reduce method to sum the values in an array. It returns the result 6.

'Hello, world!'.split('').reverse().join('') - This line uses the split, reverse, and join methods to reverse the characters in a string. It returns the result "!dlrow ,olleH".

(() => 'Hello, world!')() - This line defines and immediately invokes an anonymous arrow function that returns the string "Hello, world!". It returns the result "Hello, world!".

Array.from(Array(10), (_, i) => i + 1) - This line uses the Array.from method to create an array of 10 numbers, starting from 1. It returns the result [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].

[1, 2, 3].map(x => x * x) - This line uses the map method to square the values in an array. It returns the result [1, 4, 9].

[1, 2, 3].filter(x => x % 2 === 0) - This line uses the filter method to return only the even numbers from an array. It returns the result [2].

['a', 'b', 'c'].forEach((x, i) => console.log(x, i)) - This line uses the forEach method to log each character in a string along with its index to the console. It outputs the results "a 0", "b 1", and "c 2" to the console.

'Hello, world!'.replace(/[aeiou]/g, '*') - This line uses the replace method to replace all vowels in a string with the character "*". It returns the result "H*ll*, w*rld!".

'Hello, world!'.split(' ').join('_') - This line uses the split and join methods to replace all spaces in a string with the character "_". It returns the result "Hello,_world!".

(x => x * x)(10) - This line defines and immediately invokes an anonymous arrow function that squares its argument. It returns the result 100.