Dalam JavaScript, Anda sering perlu melakukan iterasi melalui kumpulan array dan mengeksekusi metode callback untuk setiap iterasi. Dan ada metode bermanfaat yang biasanya digunakan pengembang JS untuk melakukan ini. metode forEach()
Metode forEach()_ memanggil fungsi callback tertentu satu kali untuk setiap elemen yang diulanginya di dalam array. Sama seperti iterator array lainnya seperti map dan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
0, fungsi callback dapat menggunakan tiga parameter
Elemen saat ini. Ini adalah item dalam array yang saat ini sedang diulangi
Indeksnya. Ini adalah posisi indeks dari item tersebut di dalam array
Susunan sasaran. Ini adalah array yang sedang diulangi
Metode
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
1 tidak mengembalikan array baru seperti iterator lain seperti
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
0, map dan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
4. Sebagai gantinya, metode mengembalikan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
5 itu sendiri. Jadi itu tidak dapat dirantai seperti metode lainnya
Hal lain tentang
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
_1 adalah bahwa Anda tidak dapat menghentikan perulangan (dengan pernyataan break) atau membuatnya melewati satu iterasi (dengan pernyataan continue). Dengan kata lain, Anda tidak bisa mengendalikannya
Satu-satunya cara untuk menghentikan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
_1 loop adalah dengan melemparkan pengecualian di dalam fungsi callback. Jangan khawatir, kita akan segera melihat semua ini dalam praktik
Cara Menggunakan Metode forEach() di JavaScript
Bayangkan sekelompok siswa berbaris untuk apel rutin. Koordinator kelas bergerak melewati barisan dan memanggil nama setiap siswa sambil menandai apakah mereka hadir atau tidak hadir
Penting untuk dicatat bahwa koordinator tidak mengubah urutan siswa dalam antrean. Dia juga menjaga mereka di baris yang sama setelah dia selesai dengan absensi. Yang dia lakukan hanyalah melakukan tindakan (pemeriksaannya) pada masing-masing dari mereka
Dalam contoh berikut, dengan mengingat skenario ini, kita akan melihat bagaimana Anda dapat menggunakan metode
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
1 dalam JavaScript untuk memecahkan masalah dunia nyata
forEach() Contoh Metode dalam JavaScript
Cara Menghapus Angka Ganjil Pertama dalam Array dengan forEach()
Dalam contoh ini, kita memiliki larik yang memiliki satu bilangan ganjil di tempat pertama dan beberapa bilangan genap mengikutinya. Tapi kami hanya ingin angka dalam array ini menjadi genap. Jadi kita akan menghapus angka ganjil dari array menggunakan forEach() loop
let numbers = [3, 6, 8, 10, 12]
let odd = 3;
numbers.forEach(function(number) {
if (number === odd) {
numbers.shift() // 3 will be deleted from array
}
})
console.log(numbers);
[6, 8, 10, 12] // All even!
_
Cara Mengakses Properti Indeks dengan forEach()
Dalam contoh ini, kita akan mengeksekusi fungsi
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
_4 untuk setiap siswa yang dilingkarkan di dalam array. Fungsi
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
5 hanya mencatat string yang berkaitan dengan masing-masing siswa ke konsol
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
Dalam contoh ini, satu-satunya informasi yang kami miliki tentang setiap siswa adalah nama mereka. Namun, kami juga ingin tahu kata ganti apa yang digunakan setiap siswa. Dengan kata lain, kami ingin properti kata ganti didefinisikan untuk setiap siswa
Jadi kami mendefinisikan setiap siswa sebagai objek dengan dua properti, nama dan kata ganti
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
_
Kami mencatat pesan roll call dari setiap siswa ke konsol, lalu kami melakukan pemeriksaan untuk melihat kata ganti apa yang digunakan siswa tersebut, dan terakhir kami secara dinamis meneruskan kata ganti yang akurat sebagai bagian dari string
Cara Menyalin Array ke dalam Array Baru dengan forEach() di JavaScript
Setelah tiga tahun menempuh pendidikan, kini saatnya masing-masing mahasiswa diwisuda. Dalam JavaScript kami, kami mendefinisikan dua larik.
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
7 dan
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
8. Seperti yang mungkin Anda duga,
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
_7 memegang siswa tepat sebelum kelulusan mereka
Kemudian loop
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
_1 mengambil masing-masing siswa dan memanggil fungsi
Dalam fungsi ini kita membuat objek dengan dua properti. nama siswa serta posisi di mana mereka lulus. Kemudian kami meneruskan objek baru ke array
names = [
{name:"anna",pronoun: "she"},
{name: "beth",pronoun: "they"},
{name: "chris",pronoun: "he"},
{name: "daniel",pronoun: "he"},
{name: "ethan",pronoun: "he"}
]
function rollCall(student, index) {
console.log(`The number ${index + 1} student is ${student.name}. Is ${student.pronoun} present? Yes!`);
}
names.forEach((name, index) => rollCall(name, index));
/*
"The number 1 student is anna. Is she present? Yes!"
"The number 2 student is beth. Is they present? Yes!"
"The number 3 student is chris. Is he present? Yes!"
"The number 4 student is daniel. Is he present? Yes!"
"The number 5 student is ethan. Is he present? Yes!"
*/
8. Pada saat itu, siswa telah menjadi sarjana
Contoh ini juga menunjukkan bagaimana Anda dapat menggunakan metode forEach() untuk menyalin array ke dalam array baru
Cara Memeriksa Item Berikutnya dalam Array dengan Parameter let stillStudent = ["anna", "beth", "chris", "daniel", "ethan"]
let nowGraduated = []
function graduateStudent(student, index) {
let object = { name: student, position: index + 1}
nowGraduated[index] = object
}
stillStudent.forEach((name, index) => graduateStudent(name, index));
console.log(nowGraduated);
/*
[
{ name: "anna", position: 1},
{ name: "beth", position: 2},
{ name: "chris", position: 3},
{ name: "daniel", position: 4},
{ name: "ethan", position: 5}]
]
*/4
Pada titik tertentu, guru perlu memeriksa apakah daftar tersebut memiliki item tertentu berikutnya dalam daftar. Dalam kasus seperti itu, guru perlu memiliki pandangan yang luas dari seluruh daftar. Dengan begitu, dia dapat mengetahui apakah ada siswa berikutnya yang harus dihubungi
Dalam JavaScript kami, kami dapat mereplikasi ini karena fungsi panggilan balik juga dapat mengakses parameter
9 ke variabel. Kemudian untuk setiap iterasi, kami memeriksa apakah siswa tersebut memang yang terakhir
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
Anda tidak dapat keluar dari names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/1 Loop, Jadi Gunakan names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/1 Sebagai gantinya
Ingat ketika saya menyebutkan bahwa, secara alami, Anda tidak dapat keluar dari (alias keluar) loop
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
1? . Jadi jika Anda memasukkan pernyataan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
_3, itu akan mengembalikan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
4
let numbers = [2, 4, 5, 8, 12]
let odd = 5;
numbers.forEach(function(number) {
if (number === odd) {
break; // oops, this isn't gonna work!
}
})
_
Biasanya Anda ingin keluar dari lingkaran jika Anda akhirnya mencapai apa yang Anda inginkan sebelum mencapai item terakhir. Dalam contoh kita di atas, kita telah menemukan angka ganjil (5), jadi tidak perlu terus mengulangi item yang tersisa (8 dan 12)
Jika Anda ingin keluar dari loop dengan syarat tertentu, Anda harus menggunakan salah satu metode berikut
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
5 lingkaran
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
6 atau
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
7 putaran
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
8
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
_9
let numbers = [2, 4, 5, 8, 12]
let odd = 5;
numbers.forEach(function(number) {
if (number === odd) {
break; // oops, this isn't gonna work!
}
})
_0
Inilah cara Anda keluar dari lingkaran dengan
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index, array) {
let nextItem = index + 1 < array.length ? "postive" : "negative"
console.log(`Is the number ${index + 1} student - ${name} present? Yes!. Is there a next student? ${nextItem}!`);
}
names.forEach((name, index, array) => rollCall(name, index, array))
/*
"Is the number 1 student - anna present? Yes!. Is there a next student? postive!"
"Is the number 2 student - beth present? Yes!. Is there a next student? postive!"
"Is the number 3 student - chris present? Yes!. Is there a next student? postive!"
"Is the number 4 student - daniel present? Yes!. Is there a next student? postive!"
"Is the number 5 student - ethan present? Yes!. Is there a next student? negative!"
*/
9
let numbers = [2, 4, 5, 8, 12]
let odd = 5;
numbers.every(number => {
if (number == odd) {
return false;
}
console.log(number);
return true;
});
// 2 4
Membungkus
Dalam tutorial ini, saya telah memperkenalkan metode
names = ["anna", "beth", "chris", "daniel", "ethan"]
function rollCall(name, index) {
console.log(`Is the number ${index + 1} student - ${name} present? Yes!`)
;}
names.forEach((name, index) => rollCall(name, index));
/*
"Is the number 1 student - anna present? Yes!"
"Is the number 2 student - beth present? Yes!"
"Is the number 3 student - chris present? Yes!"
"Is the number 4 student - daniel present? Yes!"
"Is the number 5 student - ethan present? Yes!"
*/
_1, mengilustrasikan cara kerjanya dengan analogi sederhana, dan saya juga memberi Anda beberapa contoh praktis penggunaannya dalam kode JavaScript
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Bisakah saya menggunakan lanjutkan di forEach?
Dalam C#, pernyataan continue digunakan untuk melompati bagian eksekusi loop(do, while, for, or foreach) pada kondisi tertentu, after that, it transfers the control to the beginning of the loop. Basically, it skips its given statements and continues with the next iteration of the loop.
Bagaimana cara menggunakan lanjutkan di forEach di JavaScript?
Menggunakan Continue di JavaScript forEach()
. untukEach(v => { jika (v % 2. ==0) { // SyntaxError. Pernyataan lanjutan ilegal. tidak ada pernyataan iterasi di sekitarnya yang berlanjut; . We recommend using for/of loops to iterate through an array unless you have a good reason not to.
Bisakah kita menggunakan break dan continue di forEach JavaScript?
Tidak ada cara untuk menghentikan atau memutuskan loop forEach() selain dengan melemparkan pengecualian . Jika Anda memerlukan perilaku seperti itu, metode forEach() adalah alat yang salah.
Bisakah kita menggunakan pernyataan continue dan break dengan forEach loop?
Di Kotlin, kita tidak dapat secara eksplisit menggunakan pernyataan break dan continue secara eksplisit di dalam loop forEach , tetapi kita dapat menyimulasikan tindakan yang sama.
