How to SEND the content when making a GET in Javascript?

Question

I need to GET all the data of a workbook, and I tried one method, but it does not work properly.. The problem is that the Promise is returning the first line of the first worksheet, but it does not continue the process for the rest of the rows of the worksheet, respectively, all the worksheets and I don't know what to do. Maybe you know..

So I wrote this code:

const SheetGet = {
    getSheet: (req, res) => {
        return new Promise ((resolve, reject) => {
            XlsxPopulate.fromFileAsync(filePath)
                .then(workbook => {
                    const wb = xlsx.readFile(filePath, {cellDates: true});
                    const sheetNames = wb.SheetNames;
                    sheetNames.forEach(function (element){
                        let endOfData = false;
                        let i = 2;
                        let dataArr = [];
                        while (endOfData === false){
                            let taskId = workbook.sheet(element).cell("A" + i.toString()).value();
                            if (taskId !== undefined){
                                res.send({
                                    type: 'GET',
                                    list_name: element,
                                    task_id: taskId,
                                    task_name: workbook.sheet(element).cell("B" + i.toString()).value(),
                                    task_description: workbook.sheet(element).cell("C" + i.toString()).value(),
                                    task_due_date: workbook.sheet(element).cell("D" + i.toString()).value(),
                                    task_priority: workbook.sheet(element).cell("E" + i.toString()).value(),
                                    task_status: workbook.sheet(element).cell("F" + i.toString()).value(),
                                    task_notes: workbook.sheet(element).cell("G" + i.toString()).value()
                                });
                                i++;
                            }
                            else {
                                endOfData = true;
                            }
                        }
                    })
                });
        })
    }
}

It only gets this an then it stops, and I need to get all of the data from the worksheet.

Do you have any idea on how to resolve this issue? Or the proper way to make it work? Thank you very very much for your time and help!!! Much appreciated every help!!

P.S. I tried this code with "console.log", and it works very well, but the problem is when I changed to res.send, in order to get the info to Postman.

Answer 1

I assume you are using express as the framework, the problem is when you use res.send method, the server already send the data to client, while the rest of the code still running in the background. What I'm gonna do with this case are like this.

const SheetGet = {
    getSheet: (req, res) => {
        return new Promise ((resolve, reject) => {
            XlsxPopulate.fromFileAsync(filePath)
                .then(workbook => {
                    const wb = xlsx.readFile(filePath, {cellDates: true});
                    const sheetNames = wb.SheetNames;
                    sheetNames.forEach(function (element){
                        let endOfData = false;
                        let i = 2;
                        let dataArr = [];
                        while (endOfData === false){
                            let taskId = workbook.sheet(element).cell("A" + i.toString()).value();
                            if (taskId !== undefined){
                                dataArr.push({ // this one
                                    type: 'GET',
                                    list_name: element,
                                    task_id: taskId,
                                    task_name: workbook.sheet(element).cell("B" + i.toString()).value(),
                                    task_description: workbook.sheet(element).cell("C" + i.toString()).value(),
                                    task_due_date: workbook.sheet(element).cell("D" + i.toString()).value(),
                                    task_priority: workbook.sheet(element).cell("E" + i.toString()).value(),
                                    task_status: workbook.sheet(element).cell("F" + i.toString()).value(),
                                    task_notes: workbook.sheet(element).cell("G" + i.toString()).value()
                                });
                                i++;
                            }
                            else {
                                endOfData = true;
                            }
                        }
                    })
                    return res.json({ data: dataArr }); // this one
                });
        })
    }
}

While there is some unnecessary code, the least change you can do to make it works are the code above.

Cheers.