const map = (fn,arr) => arr.reduce((arr,curr)=>{
  arr.push(fn(curr));
  return arr;
},[])

const filter = (fn,arr) => arr.reduce((arr,curr)=>{
  !!fn(curr) ? arr.push(curr) : void 0
  return arr;
},[]);

const some = (fn,arr) =>  arr.reduce((bool,curr)=>{
  return !!fn(curr) || bool ? true : false
},false);

const every = (fn,arr) =>  arr.reduce((bool,curr)=>{
  return !!fn(curr) && bool ? true : false
},true);

const contains = (val,arr) =>  arr.reduce((bool,curr)=>{
  return curr === val || bool ? true : false ;
},false);