TypeScript, VBA, and the Graham Scan

Sub Graham()
Dim ob As Shape, rng As Range, sht As Worksheet, lr%, fp%
Workbooks.OpenText Filename:="C:\Users\en_sa\helloworld\example.txt", Origin _
:=xlMSDOS, StartRow:=1, DataType:=xlDelimited, TextQualifier:= _
xlDoubleQuote, ConsecutiveDelimiter:=False, Tab:=True, Semicolon:=False, _
Comma:=False, Space:=False, Other:=False, FieldInfo:=Array(Array(1, 1), _
Array(2, 1)), TrailingMinusNumbers:=True
Set sht = ActiveSheet
Set rng = sht.Columns("a:a").Find("end", LookIn:=xlValues)
fp = Split(rng.Address, "$")(2)
lr = Evaluate("=MAX((B:B<>"""")*(ROW(B:B)))")
Range(Cells(fp + 1, 1), Cells(fp + 1, 2)).Copy Cells(lr + 1, 1)
Set ob = sht.Shapes.AddChart2(240, xlXYScatterLines)
ob.Chart.SetSourceData Source:=Range("example!$A$1:$B$" & (fp - 1))
Application.CutCopyMode = False
ob.Chart.SeriesCollection.NewSeries
With ob.Chart.FullSeriesCollection(2)
    .Name = "=""sec"""
    .XValues = "=example!$A$" & (fp + 1) & ":$A$" & lr + 1
    .Values = "=example!$B$" & (fp + 1) & ":$B$" & lr + 1
    .ChartType = xlXYScatterLines
End With
With ob.Chart
    .FullSeriesCollection(1).ChartType = xlXYScatter
    .Axes(xlValue).MinimumScale = -1
    .Axes(xlCategory).MaximumScale = 11
    .HasTitle = False
End With
End Sub

interface point {
    x:number
    y:number
    angle:number
    discarded:boolean
    zero:boolean
}
import { readFileSync, writeFileSync } from 'fs';
import { join } from 'path';
let st=""
let xarr:number[]=[]
let yarr:number[]=[]
const ipt:string="file"   // data from file or not
if(ipt==="file"){reader()}
else{
for(let i=0;i<35;i++){
    xarr[i]=Math.random()*10
    yarr[i]=Math.random()*10
    st=st+xarr[i]+"\t"+yarr[i]+"\n"
}
}
st=st+"end\n"
let points:point[]=[]
for (let i = 0; i < xarr.length; i++) {
    const el: point = {
        x: Number(xarr[i]),
        y: Number(yarr[i]), angle:0 ,
        discarded: false, zero:false
    };
    points.push(el)
}
var vsort = (a: point,b: point) => {
    if (b.y < a.y) return 1;
    if (b.y > a.y) return -1;
    else {
        if (b.x < a.x) return 1;
        if (b.x > a.x) return -1;
        return 0
    }
  };
  points.sort(vsort)
  console.log("point zero="+points[0])
      for(let i=0;i<xarr.length;i++){
         points[i].angle=arcos(Number(points[0].x),Number(points[i].x),Number(points[0].y),Number(points[i].y))
        }
    var byangle=(a:point,b:point)=>{
        if(b.angle<a.angle)return 1
        if(b.angle>a.angle)return -1
        else return 0
    }
    points.sort(byangle)
    points[0].zero=true
console.log(points[points.length-1])
let curr=0
let i=0     // safety
do {
    let c1=ccw(points[curr].x,points[curr+1].x,points[curr+2].x,points[curr].y,points[curr+1].y,points[curr+2].y)
    if(c1){curr++}
    else{console.log("removed"+points.splice(curr+1,1))   // remove point
        curr-=1
  }  
    i++;
  }
  while (i < 250 && curr<points.length-2);
  for(i=0;i<points.length;i++){
    console.log(points[i].x+"  "+points[i].y)
    st=st+points[i].x+"\t"+points[i].y+"\n"
  }
  syncWF('./example.txt',st)
// end of main
function arcos(x1: number, x2: number, y1: number, y2: number) {
  let x = x2 - x1
  let y = y2 - y1
      let res= Math.acos(x / Math.sqrt(x * x + y * y))
  if(isNaN(res))res=0
      return res}
function ccw(x1:number,x2:number,x3:number,y1:number,y2:number,y3:number ) // check if it is a left turn
{let bvar= (x2-x1)*(y3-y1)-(y2-y1)*(x3-x1)>0
return bvar
}
function reader(){
  let rv=syncread('./input.txt');
  let sarr=rv.split("\n")
  console.log("len="+sarr.length)
  let i:number
  for(i=0;i<sarr.length;i++){
    let ele=sarr[i].split("\t")
    let temp1=!isNaN(Number(ele[0]))
    let temp2=!isNaN(Number(ele[1]))
    if(temp1&&temp2){
      xarr[i]=Number(ele[0])
      yarr[i]=Number(ele[1])
      console.log(i+":  "+xarr[i]+"  "+yarr[i])
      st=st+xarr[i]+"\t"+yarr[i]+"\n"
    }
  }
}
  function syncWF(fname: string, data: any) {
    /**
     * flags:
     *  - w = Open file for reading and writing. File is created if not exists
     *  - a+ = Open file for reading and appending. The file is created if not exists
     */
    writeFileSync(join(__dirname, fname), data, {      flag: 'w',    });
      return 1;
  }  
  function syncread(filename: string) {
      const cont = readFileSync(join(__dirname, filename), 'utf-8');
      return cont;
  }