function mapfilter(array, pred){
 let acc = [];
 for(let e of array){
   let a = pred(e);
   if(a !== null) acc.push(a);
 }
 return acc;
}

const tags = [
  { name: "Linux", score: .6 },
  { name: "Open Source", score: .7 },
  { name: "Bash", score: .9 },
  { name: "Shell", score: .8 },
  { name: "Awk", score: .2 },
  { name: "Sed", score: .3 },
];

let nameOfTagIfHighScore = (tag) => tag.score > 0.5 ? tag.name : null;
let result = mapfilter(tags,nameOfTagIfHighScore);