array reduce concat

array_reduce_concat.js

var arr = ['The', 'simple', 'things', 'of', 'life']

arr.reduce(function (finalString, str) {
    return finalString.concat(' ').concat(str)
}, '');
// " The simple things of life"

// reduce folds the value from left to righ, we could also reduce from right to left:
var arr = 'stressed'.split('');

arr.reduceRight(function (finalString, str) {
  return finalString.concat(str);
}, '');

// "desserts" The reversed string proves that the right most element was processed first and so on