ko.utils.arrayFirst = function（array，predicate，predicateOwner）{/ * .. * /}

Question

predicateOwner是什么意思，我找不到答案？！

像这样：

How to use indexOf in KnockoutJS

或

https://gist.github.com/hyle/8840a083bcd1325a59ca

Answer 1

arrayFirst 的最后一个参数 - 是将分配给谓词范围的上下文：

var array = ko.observableArray([1,2,3]);
var context = "Hello";
var result = ko.utils.arrayFirst(array(), function(item) {
  // 'this' is equal 'context'
  console.log(this);
  return item === 2;
}, context);

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>