SOURCE

var tradeList = [{
	"value": "TRADE_BIGDATA",
	"label": "大数据",
	"children": [{
		"value": "C",
		"label": "IaaS"
	}, {
		"value": "B",
		"label": "PaaS"
	}, {
		"value": "G",
		"label": "量化分析"
	}]
}, {
	"value": "TRADE_MACHINERY",
	"label": "机械设备",
	"children": [{
		"value": "D",
		"label": "建筑工程机械"
	}, {
		"value": "G",
		"label": "机床机械"
	}, {
		"value": "K",
		"label": "食品机械"
	}]
}, {
	"value": "TRADE_FARMING",
	"label": "农林渔牧",
	"children": [{
		"value": "I",
		"label": "生产设备"
	}, {
		"value": "D",
		"label": "林业"
	}, {
		"value": "H",
		"label": "农副产品加工"
	}, {
		"value": "F",
		"label": "畜牧业"
	}]
}, {
	"value": "TRADE_VEHICLE",
	"label": "交通工具",
	"children": [{
		"value": "B",
		"label": "船舶厂商"
	}, {
		"value": "A",
		"label": "飞机厂商"
	}]
}]

// function flatten(origin) {
//     var result = [];
//     for(var i = 0; i< origin.length; i++) {
//         var item = origin[i];
//         if(Array.isArray(item)) {
//             result = result.concat(flatten(item))
//         } else {
//             result.push(item);
//         }
//     }
//     return result;
// }

// var arr = ["a", "b", ["c", "d"], [["d"],"e"], "f"];
// flatten(arr);
// console.log(flatten(arr))


/* 数据大致解构为
 *[
 * {
 *    value:'a',
 *    label:'b',
 *    children:[{value:.....}]
 *  }
 * ]
 */

// console.log(tradeList)

// key是当前选择的某一项 如 ：
/* 
 * {
 *    value:'a',
 *    label:'b',
 *    children:[{value:.....}]
 *  }
*/
let key = [
        {
            value: "TRADE_FARMING"
        }
    ]

function getIndexByArrayKey(list, groupKey){
    let arr = list
    const data = []
    // 声明一个方法用于展开数组
    function flatten(origin, index) {
        //可以用来接收返回的值，目前没用
        const result = []
        for (let i = 0; i < origin.length; i++) {
            const item = origin[i]
            if (item.value === groupKey[index].value) {
                arr = item.children
                data.push(i)
            }
        }
        return result
    }
    for (let i = 0; i < groupKey.length; i++) {
        flatten(arr, i)
    }
    return data
}

const idnex = getIndexByArrayKey(tradeList,key)
console.log(idnex,tradeList[idnex].label)