[Strategy Pattern & Higher Order Functions] How to Switch Algorithms at Run-Time #javascript #tips

deep-truth.js

function createDeepTruthChecker(useStrategy = Object.keys) {
  return function check(obj) {
    return !!obj && (
      typeof obj === 'object'
        ? useStrategy(obj).every(key => check(obj[key]))
        : true
    );
  };
}

function NoEmptyStrategy(obj) {
  const keys = Object.keys(obj);

  return keys.length ? keys : keys.concat('length');
}

const checkDeepTruth        = createDeepTruthChecker();
const checkDeepTruthNoEmpty = createDeepTruthChecker(NoEmptyStrategy);

       checkDeepTruth({ demo: [] });         // true
checkDeepTruthNoEmpty({ demo: [] });         // false
checkDeepTruthNoEmpty({ demo: [ 'test' ]});  // true