拒绝（TypeError）：无法读取未定义、未捕获（promise中）TypeError的属性“setState”：无法读取未定义的属性“setState”

Question

我有一个简单的html" target="_blank">代码，但我收到（有时）错误的结果，这是因为nodejsasync，我知道。最后，我需要更新“this.setState（{active:options}）”。因此，为了解决NodeJS的异步问题，我使用了require（“异步”）库。但是现在我的简单代码变得相当复杂，结果也不是100%好。

同样在“函数道路”上，当我使用“this.setState（{actove:options}）”或“this.setState（{actove:results.optionsFill}）”时，我收到错误：“未处理的拒绝（TypeError）：无法读取未定义的属性‘setState’”和“未捕获（promise中）TypeError:无法读取未定义的属性‘setState’”。

请参阅简单的开始代码（该代码计算地图的图例输入、数字周期的arr）：

    setLegend(data){

        function roundingSize(number){
        }

        function rounding(number){
        }

        function stopsArrFill(jumpLegendValue, highestNumber){
        }

        // Searching for the highestNumber POPULATION
        var highestNumber = 0

        data.features.forEach(element => {
             var value = element.properties["POPULATION"]           
             if(highestNumber<value) highestNumber = value
        })

        // Need to round the number, so it will look nice on the legend
        highestNumber = roundingSize(highestNumber)

        // Searching for the LowestNumber POPULATION
        var LowestNumber = highestNumber

        data.features.forEach(element => {
            var value = element.properties["POPULATION"]
            if(LowestNumber>value) LowestNumber = value
        })

        // Need to round the number, so it will look nice on the legend
        LowestNumber = roundingSize(LowestNumber)

        // 7 because 1 element is 0 and the last is the highestNumber, so it gives 7 empty elements to fill
        var jumpLegendValue = Math.round(rounding((highestNumber - LowestNumber)/7))

        var tmpStops  = stopsArrFill(jumpLegendValue, highestNumber)

        const options = {
            name: 'Legenda',
            description: 'Liczba wystąpień',
            property: 'POPULATION',
            stops: tmpStops
        }

        this.setState({active: options})

现在async.auto的复杂代码：

    setLegend(data){

        function roundingSize(number){
        }

        function rounding(number){
        }

        function stopsArrFill(jumpLegendValue, highestNumber){
        }

        async.auto({

            highestNumber: function(callback){

                // Searching for the highestNumber POPULATION
                var highestNumber = 0

                data.features.forEach(element => {
                    var value = element.properties["POPULATION"]           
                    if(highestNumber<value) highestNumber = value
                })

                // Need to round the number, so it will look nice on the legend
                highestNumber = roundingSize(highestNumber)

                callback(null, highestNumber)
            },
            lowestNumber: ['highestNumber', function(results, callback){

                // Searching for the LowestNumber POPULATION
                var lowestNumber = results.highestNumber

                data.features.forEach(element => {
                    var value = element.properties["POPULATION"]
                    if(lowestNumber>value) lowestNumber = value
                })

                // Need to round the number, so it will look nice on the legend
                lowestNumber = roundingSize(lowestNumber)

                callback(null, lowestNumber)
            }],
            jumpLegendValue: ['highestNumber', 'lowestNumber', function(results, callback){

                // 7 because 1 element is 0 and the last is the highestNumber, so it gives 7 empty elements to fill
                var jumpLegendValue = Math.round(rounding((results.highestNumber - results.lowestNumber)/7))

                callback(null, jumpLegendValue)
            }],
            stopsArrFill:['highestNumber','jumpLegendValue', function(results, callback){

                // Filling the stops with jumpLegendValues
                var tmpStops  = stopsArrFill(results.jumpLegendValue, results.highestNumber)

                callback(null, tmpStops)
            }],
            optionsFill:['stopsArrFill', function(results, callback){

                const options = {
                    name: 'Legenda',
                    description: 'Liczba wystąpień',
                    property: 'POPULATION',
                    stops: results.stopsArrFill
                }      

                callback(null, options)
            }],
            function (err, results)
            {
                this.setState({active:results.optionsFill})
                console.log('error: ', err)
            }
        })

我现在玩这个2天了，你有什么想法/建议吗？我找不到任何类似的用法setState与async.auto.

Answer 1

要解决setState问题，您需要知道async.auto（{}）是一个promise。

最终错误函数需要删除此代码：

function (err, results)
{
    this.setState({active:results.optionsFill})
    console.log('error: ', err)
}

在async.auto（{}）末尾需要添加：

.then((result)=>{
    this.setState({active: result.optionsFill})
})