Javascript array.find() 仅在第一个实例中找到

Question

我有以下对象数组:

var data = {};

data.type = {
    "types": [{
        "testA": {
            "testVar": "abc",
            "testContent": "contentA"
        }
    }, {
        "testB": {
            "testVar": "def",
            "testContent": "contentB"
        }
    }]
};

我想做的是通过搜索它的父级和兄弟级找到它所属的对象来找到 testContent 的值:

/* within the data, find content where parent is testA and sibling testVar is "abc" */
var findSet = data.type.types.find(function(entry) {
    return entry['testA'].testVar === "abc";
});

console.log(findSet['testA'].testContent); /* returns string "contentA" as expected */

这对第一个对象工作正常但找不到下一个对象，给出错误:

Cannot read property 'testVar' of undefined

var findSet = data.type.types.find(function(entry) {
    return entry['testB'].testVar === "def"; /* Cannot read property 'testVar' of undefined */
});

console.log(findSet['testB'].testContent);

我还能如何找到需要的东西？

Here's a fiddle to test the output

Answer 1

var data = {};

data.type = {
	"types": [{
    	"testA": {
        	"testVar": "abc",
            "testContent": "contentA"
        }
    }, {
    	"testB": {
        	"testVar": "def",
            "testContent": "contentB"
        }
    }]
};

var findSet = data.type.types.find(function(entry) {
    return entry['testA'] && entry['testA'].testVar === "abc";
});

console.log(findSet['testA'].testContent);

var findSet = data.type.types.find(function(entry) {
    return entry['testB'] && entry['testB'].testVar === "def"; /* Cannot read property 'testVar' of undefined */
});

console.log(findSet['testB'].testContent);

在测试他的属性之前，先检查你的条目是否存在。