-
some()
Tests whether at least one element in the array passes the test implemented by the provided function.
const people = [
{ name: 'Wes', year: 1988 },
{ name: 'Kait', year: 1986 },
{ name: 'Irv', year: 1970 },
{ name: 'Lux', year: 2015 }
];
// Array.prototype.some() // is at least one person 19 or older?
let anyOlderThan19 = people.some(person => {
let age = new Date().getFullYear() - person.year;
return age > 18;
});
console.log(anyOlderThan19);
>> true
-
every()
Tests whether all elements in the array pass the test implemented by the provided function.
// Array.prototype.every() // is everyone 19 or older?
let allOlderThan19 = people.every(person => {
let age = new Date().getFullYear() - person.year;
return age > 18;
});
console.log(allOlderThan19);
>> false
-
find()
Returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned.
const comments = [
{ text: 'Love this!', id: 523423 },
{ text: 'Super good', id: 823423 },
{ text: 'You are the best', id: 2039842 },
{ text: 'Ramen is my fav food ever', id: 123523 },
{ text: 'Nice Nice Nice!', id: 542328 }
];
/ find the comment with the ID of 823423
let comment = comments.find(comment => comment.id === 823423);
console.log(comment);
>> { id: 823423, text: "Super good" }
-
findIndex()
Returns the index of the first element in the array that satisfies the provided testing function. Otherwise -1 is returned.
// Find the comment with this ID
// delete the comment with the ID of 823423
let commentIndex = comments.findIndex(comment => comment.id === 823423);
comments.splice(commentIndex, 1);
console.log(comments);
[
{ text: "Love this!", id: 523423 },
{ text: "You are the best", id: 2039842 },
{ text: "Ramen is my fav food ever", id: 123523 },
{ text: "Nice Nice Nice!", id: 542328}
]