var arr=[1,2,3,4,5,6,100,999]
arr.sort((a,b)=>{
  if (a%2==b%2) return a-b;
  if (a%2>b%2) return -1;
  return 1;
})
console.log(arr)

var a=[1,2,3,4,5];
console.log(a.every(x=>x>0));                             
console.log(a.every(x=>x>1)); 

❓Что будет на выходе?

var a=[1,2,3,4,5];
a.every(x=>{
  console.log(x); 
  return x<4;
})

var str="             abc                ";
console.log(str.trim());
str="\n\n\n\nabc\t\t\t"
console.log(str.trim());

function plus(a,b){
  console.log(`${a} + ${b} = ${a+b}`);
}
plus(1,2);
plus(3,4);

function repeatIt(s){
  console.log(`${s} ${s} ${s}`);
}
repeatIt `a`;
repeatIt `ab`;

var num=111;
var a=num.toFixed(), 
    b=num.toExponential(), 
    c=num.toPrecision()
console.log([a,b,c])

var num=111;
var a=num.toFixed(), 
    b=num.toExponential(), 
    c=num.toPrecision()
console.log([a,b,c])

var num=111.11;
var a=num.toFixed(6), 
    b=num.toExponential(6), 
    c=num.toPrecision(6)
console.log([a,b,c]) 

var num=111.11;
var a=num.toFixed(6), 
    b=num.toExponential(6), 
    c=num.toPrecision(6)
console.log([a,b,c]) 

var a=[1,2,3,4,5];
var b=a.filter(function(x){return x<3});
console.log(b);

var a=[3,6,9,12,24,36]
var b=a.filter(x=>x%2==0&&x%3==0&&x%4==0)
console.log(b)

var str="abcde";
console.log(str.charAt(0));
console.log(str.charAt(1));

var str="abcde";
console.log(str[0]);
console.log(str[1]);

var str="abcde";
for (var i=0;i<str.length;i++){
  console.log(str.charAt(i),str.charCodeAt(i));
}

var a=[1,4,9,16]
var b=a.map(Math.sqrt)
console.log(a) 
console.log(b)

var a=[1,2,3,4]
var b=a.map(x=>x+1)
console.log(a)
console.log(b)

var a=[...Array(4)]
var b=a.map((_,i)=>i)
var c=[...Array(4)].map((_,i)=>i)  
var d=Array.prototype.map.call(a,(_,i)=>i)
console.log(a)  
console.log(b)   
console.log(c)   
console.log(d)

var str="My name is John";
console.log(str.toUpperCase());
console.log(str.toLowerCase());