I have reviewed similar questions and most seem to concern this, mine doesn't. I am trying to create a new property that is a function expression on objects in an array but the property returns undefined. I need it to return function
Here is a fiddle version.
let athleteArray = [
rupert = {
name: 'Mike',
age: '33',
sport: 'sitting',
quote: 'Hello Super nintendo chalmers'
},
alice = {
name: 'Bill',
age: '35',
sport: 'cooking',
quote: 'stop that'
}
];
const win = function(name, sport) {
console.log(`${name} won the ${sport} event!`)
}
//loop to add new 'win' property
for (let i = 0; i < athleteArray.length; i++) {
athleteArray[i].win = win(athleteArray[i].name,
athleteArray[i].sport)
console.log(athleteArray[i])
console.log(typeof(athleteArray[i].win))
}Use a class where you can define your methods.
class Person {
constructor(details) {
this.name = details.name || 'Unknown';
this.age = details.age || 'Unknown';
this.sport = details.sport || 'Unknown';
this.quote = details.quote || 'Unknown';
}
win () {
return `${this.name} won the ${this.sport} event!`;
}
}
const athleteArray = [
new Person({
name: 'Mike',
age: '33',
sport: 'sitting',
quote: 'Hello Super nintendo chalmers'
}),
new Person({
name: 'Bill',
age: '35',
sport: 'cooking',
quote: 'stop that'
})
];
athleteArray.forEach(person => console.log(person.win()));If you want to do it your way, you need to create a function. You just assign what it returns to the property
let athleteArray = [
rupert = {
name: 'Mike',
age: '33',
sport: 'sitting',
quote: 'Hello Super nintendo chalmers'
},
alice = {
name: 'Bill',
age: '35',
sport: 'cooking',
quote: 'stop that'
}
];
const win = function(name, sport) {
console.log(`${name} won the ${sport} event!`)
}
//loop to add new 'win' property
for (let i = 0; i < athleteArray.length; i++) {
athleteArray[i].win = () => win(athleteArray[i].name,
athleteArray[i].sport)
console.log(athleteArray[i])
console.log(typeof athleteArray[i].win)
athleteArray[i].win();
}You have to return something from the win function:
let athleteArray = [
rupert = {
name: 'Mike',
age: '33',
sport: 'sitting',
quote: 'Hello Super nintendo chalmers'
},
alice = {
name: 'Bill',
age: '35',
sport: 'cooking',
quote: 'stop that'
}
];
const win = function(name, sport) {
return `${name} won the ${sport} event!`;
}
//loop to add new 'win' property
for (let i = 0; i < athleteArray.length; i++) {
athleteArray[i].win = win(athleteArray[i].name,
athleteArray[i].sport)
console.log(athleteArray[i])
console.log(typeof athleteArray[i].win )
}The 'win' function does not return anything. The way you wrote the code, 'athleteArray[i].win' will be undefined. To do what you want, you should do something like that:
athleteArray[i].win = () => win(athleteArray[i].name, athleteArray[i].sport)
It's easier to understand the error if the code were like that:
const returnedValue = win(athleteArray[i].name, athleteArray[i].sport)
// Returned value is undefined
athleteArray[i].win = returnedValue