React state 未定义，即使 console.log 显示它

Question

I have researched other cases when the state was unidentified but I am still unsuccessfully trying to subtract data from UI actions that is in the format [{},{}...]. I have managed to add to the array, using this code, which in the same time also computes the total for the item (subTotal and products are props from a child component got through a callback function):

const updateTotalPriceAndUpdatePieChartData = (subTotal,product) => {
        //from here   
        setPieChartData([...pieChartData,{product,subTotal}])
        //until up, we handle what data we need for the pieChart
        setTotal(total => total + (Number.isFinite(subTotal) ? subTotal : 0))
        console.log("TOTAL WAS COMPUTED")
    }

And this is the state that holds the array:

const [pieChartData,setPieChartData]=React.useState([])

Yet when I try to delte an object from the state array (when an item is also deleted), I try the following:

const substractSubTotalAndSubstractTotalForPieChart = (subTotal,product,pieChartData) => {
    setTotal(total - subTotal)
    const lastPieChartData=pieChartData.filter(item => item !={subTotal,product})
    setPieChartData(lastPieChartData)
}

It says that pieChartData is unidentified. Could you please let me know what I can do?

Answer 1

In substractSubTotalAndSubstractTotalForPieChart method, there is a paramter pieChartData , but there is also a state with the same name . So what happens is inside the function substractSubTotalAndSubstractTotalForPieChart's scope, the parameter pieChartData is given preference rather than the state.

Hence in your method invocation, when you don't pass this parameter, the default value of an uninitialized parameter, ie, undefined is used.