ecma6最短的循环，如果检查

Question

what is the shortest way to achieve this for loop in ecmascript 6:

var data = {
        sales: [
            {
                name: "Jim Frost",
                region: "USA East",
                phone: "212-555-1212",
                email: "jfrost@acme-travel.com"
            },
            {
                name: "Jan Smith",
                region: "USA West",
                phone: "310-555-1212",
            }
        ]
};

here is my attempt to see if the key is equal to my manually set variable, then i change that key item's field, if not, i change it to something else.

var str = '0'; // could also be an integer
for (var key in data.sales) {
  key ===  str ? data.sales[key].region = 'StateChosen' : data.sales[key].region = 'stateEliminated';
}

what is the shortest way to achieve this using ecma6, object.keys, map, filter, every, etc methods?

Answer 1

Your example could be done just by doing:

data.sales.forEach(el => el.region = 'stateEliminated'); // Change every region to eliminated
data.sales[str].region = 'StateChosen'; // Change back the selected to StateChosen.

Note: I am assuming that str is a valid key in data.sales .

Answer 2

A for of loop with destructuring assignment and .entries() would help.

for (let [k, v] of data.sales.entries())
  v.region = k == str ? 'StateChosen' : 'stateEliminated';

 var data = { sales: [ { name: "Jim Frost", region: "USA East", phone: "212-555-1212", email: "jfrost@acme-travel.com" }, { name: "Jan Smith", region: "USA West", phone: "310-555-1212", } ] }; var str = '0'; for (var [k, v] of data.sales.entries()) v.region = k == str ? 'StateChosen' : 'stateEliminated'; console.log(data);