ZIP interleaved array into object

zipInterleaved.js

function zipInterleaved(arr) {
  return arr.reduce( (prev, cur, idx) => {
    if (idx % 2 == 0) {
       return {obj:prev, key:cur};
    } else {
       let obj = prev.obj;
       obj[prev.key] = cur;
       return prev.obj;
    }
  }, {});
}

/**
 * usage: zipInterleaved(['foo', 'bar', 'magic', 'custard'])
 * result: { foo: 'bar', magic: 'custard' }
 */