Tag Archives: Excel

JavaScript: In-browser export to CSV

This function will turn an array of data into a CSV file and get the browser to “download” it. It should also be wrapping and escaping values properly and, because of the BOM, be read correctly when opened in e.g. Excel.

It’s written in TypeScript ("lib": ["ES2017", "DOM"]), but should be easy to “downgrade” to regular JS if needed…

type GetValue <T> = <I extends T>(item: I) => any;
type FieldName <T> = keyof T;

export interface Columns<T> {
  [s: string]: FieldName<T> | GetValue<T>;
}

const COLUMN_SEPARATOR = ';';
const ROW_SEPARATOR = '\r\n';
const UNICODE_BOM = '\uFEFF';

const wrapValue = (value: string) => `"${value}"`;
const escapeValue = (value: string) => (value || '').replace(/"/, '""');

const toHeaderRow = <T> (columns: Columns<T>) => Object
  .keys(columns)
  .map(escapeValue)
  .map(wrapValue)
  .join(COLUMN_SEPARATOR);

const toRow = <T> (columns: Columns<T>, item: T) => Object
  .values(columns)
  .map(field => typeof field === 'function' ? field(item) : item[field])
  .map(String)
  .map(escapeValue)
  .map(wrapValue)
  .join(COLUMN_SEPARATOR);

export const exportToCsv = function <T> (data: T[], columns: Columns<T>, filename: string): void {
  const rows = [];

  rows.push(toHeaderRow(columns));

  for (const item of data) {
    rows.push(toRow(columns, item));
  }

  const csv = UNICODE_BOM + rows.join(ROW_SEPARATOR);
  const uri = `data:text/csv;charset=utf-8;header=present,${encodeURIComponent(csv)}`;

  const link = document.createElement('a');
  link.setAttribute('href', uri);
  link.setAttribute('download', filename);
  link.addEventListener('click', () => link.parentNode.removeChild(link));
  document.body.appendChild(link);

  link.click();
};

Usage

const users: User[] = [{id: 1, name: 'Alice', isCool: true}, ...];
const columns: Columns<User> = {
  'Id': 'id',
  'Name': 'name',
  'Is cool': user => user.isCool ? 'Yes' : 'No',
};
exportToCsv(users, columns, 'users.csv');

Excel: Function for nslookup in worksheet

Just a copy of a function I found in a blog post for doing nslookup calls in a worksheet, in case I need it again in the future. I’ve changed the return value for failing lookups to a blank string, “”, rather than “NotFound”, but otherwise it’s unchanged.

Usage, given an IP in cell A1, to get the hostname: =NSLookup(A1; 2)

Public Function NSLookup(lookupVal As String, Optional addressOpt As Integer) As String
   Const ADDRESS_LOOKUP = 1
   Const NAME_LOOKUP = 2
   Const AUTO_DETECT = 0
   
   'Skip everything if the field is blank
   If lookupVal <> "" Then
        Dim oFSO As Object, oShell As Object, oTempFile As Object
        Dim sLine As String, sFilename As String
        Dim intFound As Integer
        Set oFSO = CreateObject("Scripting.FileSystemObject")
        Set oShell = CreateObject("Wscript.Shell")
       
        'Handle the addresOpt operand
        'Regular Expressions are used to complete a substring match for an IP Address
        'If an IP Address is found, a DNS Name Lookup will be forced
        If addressOpt = AUTO_DETECT Then
            ipLookup = FindIP(lookupVal)
            If ipLookup = "" Then
                addressOpt = ADDRESS_LOOKUP
            Else
                addressOpt = NAME_LOOKUP
                lookupVal = ipLookup
            End If
        'Do a regular expression substring match for an IP Address
        ElseIf addressOpt = NAME_LOOKUP Then
            lookupVal = FindIP(lookupVal)
        End If
       
        'Run the nslookup command
        sFilename = oFSO.GetTempName
        oShell.Run "cmd /c nslookup " & lookupVal & " > " & sFilename, 0, True
        Set oTempFile = oFSO.OpenTextFile(sFilename, 1)
        Do While oTempFile.AtEndOfStream <> True
            sLine = oTempFile.Readline
            cmdStr = cmdStr & Trim(sLine) & vbCrLf
        Loop
        oTempFile.Close
        oFSO.DeleteFile (sFilename)
       
        'Process the result
        intFound = InStr(1, cmdStr, "Name:", vbTextCompare)
        If intFound = 0 Then
            NSLookup = ""
            Exit Function
        ElseIf intFound > 0 Then
            'TODO: Cleanup with RegEx
            If addressOpt = ADDRESS_LOOKUP Then
                loc1 = InStr(intFound, cmdStr, "Address:", vbTextCompare) + InStr(intFound, cmdStr, "Addresses:", vbTextCompare)
                loc2 = InStr(loc1, cmdStr, vbCrLf, vbTextCompare)
                nameStr = Trim(Mid(cmdStr, loc1 + 8, loc2 - loc1 - 8))
            ElseIf addressOpt = NAME_LOOKUP Then
                loc1 = InStr(intFound, cmdStr, "Name:", vbTextCompare)
                loc2 = InStr(loc1, cmdStr, vbCrLf, vbTextCompare)
                nameStr = Trim(Mid(cmdStr, loc1 + 5, loc2 - loc1 - 5))
            End If
        End If
        NSLookup = nameStr
    Else
        NSLookup = "N/A"
    End If
End Function

Function FindIP(strTest As String) As String
    Dim RegEx As Object
    Dim valid As Boolean
    Dim Matches As Object
    Dim i As Integer
    Set RegEx = CreateObject("VBScript.RegExp")
   
    RegEx.Pattern = "\b(?:\d{1,3}\.){3}\d{1,3}\b"
    valid = RegEx.test(strTest)
    If valid Then
        Set Matches = RegEx.Execute(strTest)
        FindIP = Matches(0)
    Else
        FindIP = ""
    End If
End Function

Source: jayteknews.blogspot.no