I am looping through my array to get the corresponding field value:
var someFun = function (nm) {
var names = [{name: 'joe', age: 'nine'}, {name: 'tom', age: 'ten'}];
for (var i=0; i < names.length; i++) {
if (names[i].name === nm) return names[i].age;
}
};
var username = 'tom';
var printme = someFun(username);
console.log('hey: ', printme)
How can I do the same using Object.keys(), or map, or forEach? Much cleaner and ES6 compliant.
Simply use find
([{name: 'joe', age: 'nine'}, {name: 'tom', age: 'ten'}].find( (s)=> s.name=="tom" )||{}).age //10
([{name: 'joe', age: 'nine'}, {name: 'tom', age: 'ten'}].find( (s)=> s.name=="tom2" )||{}).age //undefined
Demo
var names = [{
name: 'joe',
age: 'nine'
}, {
name: 'tom',
age: 'ten'
}];
function getAge(names, name) {
return (names.find((s) => s.name == name) || {}).age;
}
console.log(getAge(names, "tom"))
console.log(getAge(names, "tom2"))
You can use array.prototype.find:
var names = [{name: 'joe', age: 'nine'}, {name: 'tom', age: 'ten'}];
var someFun = (nm) => {
var found = names.find(el => el.name === nm);
return found && found.age || null;
}
console.log(someFun('tom'));The find() method returns the value of the first element in the array that satisfies the provided testing function.
If there are multiples objects with the same name?
var names = [{
name: 'joe',
age: 9
},
{
name: 'tom',
age: 10
},
{
name: 'frank',
age: 9
},
{
name: 'joe',
age: 15
}
];
function getData(arr, search) {
// Filter array of objects by a search pair
return arr.filter(o => o[search[0]] === search[1]);
}
function listBy(arr, k) {
// Output values from an array of objects by a key as a comma separated string
return arr.map(o => o[k]).join(",");
}
console.log(getData(names, ["name", "joe"]));
console.log(listBy(getData(names, ["name", "tom"]), "age"));
console.log(listBy(getData(names, ["age", 9]), "name"));IE doesn't support find, check the Browser compatibility. Maybe you don't need to support IE, but it's still a gets 3.74% of global usage as of Oct 2017. However, it does support filter.
var users = [
{ name: "Bill", age: 'nine' },
{ name: 'Tedd', age: 'ten' }
];
function getAgeFromUsers(name) {
const arr = users.filter(u => u.name === name);
return !!arr.length ? arr[0].age : "That user ain't here";
}
console.log(getAgeFromUsers('Tedd'));
console.log(getAgeFromUsers("Lion 'O"));
var someFun = nm => {
const names = [{name: 'joe', age: 'nine'}, {name: 'tom', age: 'ten'}];
const foundName = names.find(name => name.name === nm)
return foundName ? foundName.age : null
};
This replicates what you have above. Although i would personally return the object then age the age from that instead of just returning the age.
boy, not foundName though
namesis an array. You would not useObject.keys!return {joe: 'nine', tom: 'ten'}[nm];would do the job :-)for(var key in names[i]){ console.log("key: " + key + ", value: " + names[i][key]); }