const nums = [1,2,3,4,5,6,7,8,9,10];
const o = document.getElementById('output');
o.innerHTML =
'nums = '+JSON.stringify(nums)+'
'+
'.map(n => n*2) → '+JSON.stringify(nums.map(n=>n*2))+'
'+
'.filter(n => n%2===0) → '+JSON.stringify(nums.filter(n=>n%2===0))+'
'+
'.find(n => n>5) → '+nums.find(n=>n>5)+'
'+
'.reduce((a,b) => a+b) → '+nums.reduce((a,b)=>a+b)+'
'+
'.some(n => n>8) → '+nums.some(n=>n>8)+'
'+
'.every(n => n>0) → '+nums.every(n=>n>0)+'
'+
'.includes(5) → '+nums.includes(5)+'
'+
'.slice(2,5) → '+JSON.stringify(nums.slice(2,5));