javascript - JSON : fetch mapping data

Question

摘要:

共有三个dropdowns对于每个 levelNum 。例如 levelNum2 的下拉列表包含 (Department-Unit-1, Department-Unit-2 & Department-Unit-3) ,levelNum3 包含 (Division-Unit-1 & Division-Unit-2) levelNum4 包含 (Business-Unit-1 & Business-Unit-2) .

有一个array of objects每个对象内部都有一个名为 hierarchyLevels 的属性。 这又是 array of objects每个对象内部都有两个属性unitName & levelNum 如下图JSON .

var data = [{
    "hierarchyLevels": [{
        "unitName": "Department-Unit-3",
        "levelNum": 2
    }, {
        "unitName": "Division-Unit-2",
        "levelNum": 3
    }, {
        "unitName": "Business-Unit-1",
        "levelNum": 4
    }]
}, {
    "hierarchyLevels": [{
        "unitName": "Department-Unit-1",
        "levelNum": 2
    }, {
        "unitName": "Division-Unit-1",
        "levelNum": 3
    }, {
        "unitName": "Business-Unit-2",
        "levelNum": 4
    }]
}, {
    "hierarchyLevels": [{
        "unitName": "Department-Unit-2",
        "levelNum": 2
    }, {
        "unitName": "Business-Unit-1",
        "levelNum": 4
    }]
}]

到目前为止尝试过:

function getMultipleObjectFromList(propertyName, value, list){
    return list.filter(function (item) {
        return item.hierarchyLevels.some(function (level) {
            return level[propertyName] === value;
        });
    });
};

var res = getMultipleObjectFromList('unitName','Business-Unit-1',data);

要求:

我想要fetch所有unitName与另一个相关unitName 。所以，如果我选择Business-Unit-1来自levelNum4下拉列表，另一个低级下拉列表将自动填充 unitName与 Business-Unit-1 相关.即levelNum3下拉列表将仅包含 Division-Unit-2和levelNum2下拉列表将包含 (Department-Unit-2 & Department-Unit-3) .

Answer 1

您的数据结构的级别比您在函数中处理的级别还要多。您省略了 hierarchyLevels 属性，它是一个数组，您无需对其进行迭代。

这里是一个建议的改编函数，它返回那些匹配的hierarchyLevels。我还添加了一个类似的函数，当存在匹配时返回内部对象，而不是 hierarchyLevels 数组。该选项可用于填充您的下拉列表:

function getMultipleObjectFromList(propertyName, value, list){
    return list.filter(function (item) {
        return item.hierarchyLevels.some(function (level) {
            return level[propertyName] === value;
        });
    });
};

function getDetailFromList(propertyName, value, list){
    return list.map(function (item) {
        return item.hierarchyLevels.filter(function (level) {
            return level[propertyName] === value;
        }).pop(); // only return single match
    }).filter(function (item) { // exclude null
        return item;
    }); 
};


var data = [{
    "hierarchyLevels": [{
        "unitName": "Department-Unit-3",
        "levelNum": 2
    }, {
        "unitName": "Division-Unit-2",
        "levelNum": 3
    }, {
        "unitName": "Business-Unit-1",
        "levelNum": 4
    }]
}, {
    "hierarchyLevels": [{
        "unitName": "Department-Unit-1",
        "levelNum": 2
    }, {
        "unitName": "Division-Unit-1",
        "levelNum": 3
    }, {
        "unitName": "Business-Unit-2",
        "levelNum": 4
    }]
}, {
    "hierarchyLevels": [{
        "unitName": "Department-Unit-2",
        "levelNum": 2
    }, {
        "unitName": "Business-Unit-1",
        "levelNum": 4
    }]
}];

var res = getMultipleObjectFromList('unitName','Business-Unit-1',data);

var level2 = getDetailFromList('levelNum', 2, res);

var level3 = getDetailFromList('levelNum', 3, res);

var output = '<h2>filtered data:</h2>' + JSON.stringify(res, null, 4) + '\n'
           + '<h2>level 2:</h2>' + JSON.stringify(level2, null, 4)  + '\n'
           + '<h2>level 3:</h2>' + JSON.stringify(level3, null, 4);

document.querySelector('pre').innerHTML = output;

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