在深度嵌套的对象数组中搜索单个键

Question

我正在尝试搜索深度嵌套的数组，并查找其中是否存在键。我已经写了一段代码来执行遍历，但是因为它不是递归的(只是自调用(，所以它无法返回它是否找到了任何东西。它只是返回undefined因为它在其中一个传递中到达函数的末尾。

我想知道是否有一种方法可以做到这一点，允许我在第一次出现特定密钥时返回true。

这是我到目前为止一直在使用的JS垃圾箱：

https://jsbin.com/qaxuwajuso/edit?js,console

这是上面示例中代码的直接粘贴：

function traverse(item, key) {
if (typeof item === 'object' && !Array.isArray(item) && item !== null) {
// Object
for (let itemKey in item) {
if (itemKey === key) {
// Is it possible to return true and break out of the function here?
console.log('found the key: ' + itemKey + ' With value: ' + item[itemKey]);
}
traverse(item[itemKey], key);
}
} else if (Array.isArray(item)) {
// Array
for (let i = 0; i < item.length; ++i) {
traverse(item[i], key);
}
}
}

任何帮助将不胜感激。谢谢你的时间！

Answer 1

当然，您只需要返回某种标志即可触发循环停止

/*
* I am trying to search the following json array for any occurance of the key "statePath".
* In a perfect world I would be able to find the first occurance, and return true from the
* function.
*
* The following data is not real, I was just trying to write as much nested stuff as possible
* to test that it traverses as far as needed.
*/
const data = [
{
id: '2144d998-4c33-4b03-93d2-f6c675b24508',
element: 'div',
props: {
className: 'testing',
name: [
{
first: 'John',
last: {
statePath: 'lastName',
anArray: [
{
anObject: {
anotherArray: [
{
doesItWork: {
statePath: 'hello',
},
},
],
},
},
],
},
},
{
first: 'Jane',
last: {
statePath: 'lastName',
},
},
],
},
children: 'hi',
},
];
function traverse(item, key) {
if (typeof item === 'object' && !Array.isArray(item) && item !== null) {
// Object
for (let itemKey in item) {
if (itemKey === key) {
console.log('found the key: ' + itemKey + ' With value: ' + item[itemKey]);

// not sure what you want the end "return" of the func to be, I'm returning the value.  You could return true here instead, you could return a reference to the parent object, lots of possibilities
return item[itemKey];
}
var found = traverse(item[itemKey], key);
if (found !== undefined) return found;
// otherwise keep looking
}
} else if (Array.isArray(item)) {
// Array
for (let i = 0; i < item.length; ++i) {
var found = traverse(item[i], key);
if (found !== undefined) return found;
}
}
}
var value = traverse(data, 'statePath');
console.log("value is " + value);

Answer 2

您可以使用for...in并将结果存储在一个 var 中，然后在再次调用函数之前检查该 var，并在找到值时中断循环。

const data = [{"id":"2144d998-4c33-4b03-93d2-f6c675b24508","statePath":"div","props":{"className":"testing","name":[{"first":"John","last":{"statePath":"lastName","anArray":[{"anObject":{"anotherArray":[{"doesItWork":{"statePath":"hello"}}]}}]}},{"first":"Jane","last":{"statePath":"lastName"}}]},"children":"hi"}]
function traverse(item, key) {
let result = false;
for (var i in item) {
if (i == key) {
result = true;
break;
}
if (typeof item[i] == 'object' && !result) {
result = traverse(item[i], key)
}
}
return result
}
console.log(traverse(data, 'statePath'))

Answer 3

我的变体：

const data = [{id: '2144d998-4c33-4b03-93d2-f6c675b24508', element: 'div', props: {className: 'testing', name: [{first: 'John', last: {statePath3: 'lastName', anArray: [{anObject: {anotherArray: [{doesItWork: {statePath1: 'hello',},},],},},],},}, {first: 'Jane', last: {statePath: 'lastName',},},],}, children: 'hi',},];
function traverse(data, find) {
for (let k in data) {
let deepHaveKey = typeof data[k] === 'object' && traverse(data[k], find)

if (find === k || deepHaveKey)
return true
}

return false
}
console.log(traverse(data, 'statePath')); // true
console.log(traverse(data, 'state')); // false