JavaScript Array findIndex()

Tafarki da Amfani

findIndex() Koyarwa ake karawa kuma yankin farko na baƙin da ke tafiyar da shi (a matsayin koyarwa a ke kara wa shi).

findIndex() Koyarwa kai gudanar da koyarwa a kowace yankin baƙin:

  • Idan ana samun baƙin da kuma ake kara wa shi true, findIndex() ake karawa kuma yankin farko na baƙin na yau.
  • Bai sake kawar dake yankin farko na baƙin da ba da mutum ba.

Tattalin:findIndex() Bai sake kawar dake yankin farko na baƙin da ba da mutum ba.

Tattalin:findIndex() Bai sake kawar dake yankin farko ba.

Matafi

Tarihin 1

Gyaran baƙin da ke kewayawa 18 ko ya kwaya kewayawa na farko:

var ages = [3, 10, 18, 20];
function checkAdult(age) {
  return age >= 18;
}
function myFunction() {
  document.getElementById("demo").innerHTML = ages.findIndex(checkAdult);
}

Duba kansu

Example 2

Obtaining the index of the first element in an array greater than a specific number:

<p>Minimum age: <input type="number" id="ageToCheck" value="18"></p>
<button onclick="myFunction()">Try it</button>
<p>Any ages above: <span id="demo"></span></p>
<script>
var ages = [4, 12, 16, 20];
function checkAdult(age) {
  return age >= document.getElementById("ageToCheck").value;
}
function myFunction() {
  document.getElementById("demo").innerHTML = ages.findIndex(checkAdult);
}
</script>

Duba kansu

Girmamman

array).findIndex(function(currentValue, index, arr, thisValue)

Mutum na fannin

Mutum Bayani
function(currentValue, index, arr) Dauka. Fannin wanda zai amfani dashi don kai kowane abin na tashin hanyar.

Mutum na fannin:

Mutum Bayani
currentValue Dauka. Wurin abin da yake sa.
index Dukkanci. Index na abin da yake sa cikin abin.
arr Dukkanci. Babban abin na tashin hanyar wanda yana cikin abin da yake sa.
thisValue

Dukkanci. Dake na amfani dashi don kewaye "this" na fannin.

Bai zama wanda ake amfani dashi kuma yana kewaye "this" na tsawon zai samu.

Babban abin girmamman

Kiyaye: Bai dake na kaiyawa da kananin wani abun na tashin hanyar ta amfani, kuma kuma yana daya -1.
Banin JavaScript: ECMAScript 6

Dukwanci na browsers

Lamun dake na tabbin gane na kwararru a kanayya yau bayan kwararru na farko a kwararru na browsers

Chrome Edge Firefox Safari Opera
Chrome 45 Edge 12 Firefox 25 Safari 7.1 Opera 32
2015 shekaru 9 2015 shekaru 7 2014 shekaru 7 2014 shekaru 9 2015 shekaru 9

Tattalin:Internet Explorer ǹgbarau findIndex() 方法。

相关页面

教程：JavaScript 数组

教程：JavaScript 数组 Const

教程：JavaScript 数组方法

教程：JavaScript 排序数组

教程：JavaScript 数组迭代