javascript - 声明对象数组时的函数作用域问题

Question

这是我目前拥有的代码，发生的一个问题是我无法使用 test() 因为 presets[index].name 和 value 在它们的函数范围之外是不可见的，我应该如何在全局范围内声明我的对象数组，以便我能够在其他函数中访问这两个变量？

var presets = [];
var index;

function CreatePresetArray(AMib, AVar) {
    var parentpresetStringOID = snmp.getOID(AMib, AVar);
    var presetStringOID = parentpresetStringOID;
    parentpresetStringOID = parentpresetStringOID.substring(0, parentpresetStringOID.length - 2);
    log.error("parentpresetStringOID is " + parentpresetStringOID);

    var presetswitches = {};

    for (var i = 1; i < 41; i++) {
        presets.push(presetswitches);
        try {
            log.error("presetStringOID before getNextVB= " + presetStringOID);
            vb = snmp.getNextVB(presetStringOID);
            presetStringOID = vb.oid;
            log.error("presetStringOID  after getnextVB= " + presetStringOID);

            var presetStringVal = snmp.get(presetStringOID);

            log.error("presetStringVal= " + presetStringVal);

            index = i - 1;

            presets[index].name = presetStringOID;
            presets[index].value = presetStringVal;
            log.error("preset array's OID at position [" + index + "]     is" + presets[index].name + " and the value stored is " + presets[index].value);

            //log.error("presets Array value ["+index+"] =     "+presets[index].configs);

            if (presetStringOID.indexOf(parentpresetStringOID) != 0) {
                break;
            }

        } catch (ie) {
            log.error("couldn't load preset array " + index);
        };
    };
}

CreatePresetArray(presetMib, "presetString");

function test() {
    for (i = 1; i < 41; i++) {
        log.error("test" + presets[index].name + "        " + presets[index].value);
    };
}
test();

Answer 1

test 函数中的 for 循环遍历 i 但在循环内使用 index。也许你打算使用

for (i = 0; i < 40; i++) { // 1 lower as you were using `index = i - 1` before
    log.error("test" + presets[i].name + "        " + presets[i].value);
}

---

重新编写您的代码。我不认为我通过改变赚了那么多钱。如果这不能解决您的问题，请考虑: catch 是否在每次迭代中发生？问题实际上是否来自仅在此处可见的不同方法？此外，考虑在调试时记录整个 presets Array 以查看其外观。

var presets = [];

function CreatePresetArray(AMib, AVar) {
    var parentPresetOID, presetOID, presetValue, preset, vb, i;
    parentPresetOID = snmp.getOID(AMib, AVar);
    presetOID = parentPresetOID; // initial
    parentPresetOID = parentPresetOID.substring(0, parentPresetOID.length - 2);

    log.error("parentPresetOID is " + parentPresetOID);
    presets = []; // empty array in case not already empty
    for (i = 0; i < 40; ++i) {
        try {
            preset = {}; // new object
            // new presetOID
            vb = snmp.getNextVB(presetOID);
            presetOID = vb.oid;
            log.error("presetOID  after getnextVB= " + presetOID);
            // new value
            presetValue = snmp.get(presetOID);
            log.error("presetValue= " + presetValue);
            // append data to object
            preset.name = presetOID;
            preset.value = presetValue;
            // append object to array
            presets.push(preset);
            // more logging
            log.error(
                "preset array's OID at position [" + i + "]" +
                "     is" + presets[i].name + " and " +
                "the value stored is " + presets[i].value
            );
            if (presetOID.indexOf(parentPresetOID) !== 0) {
                break;
            }
        } catch (ie) {
            log.error("couldn't load preset array " + i);
            if (presets.length !== i + 1) { // enter dummy for failed item
                presets.push(null);
            }
        }
    }
}