src/core/converters/convertImageToPng.mts

import sharp from "sharp"

export async function convertImageToPng(imgBase64: string = ""): Promise<string> {

  const base64WithoutHeader = imgBase64.split(";base64,")[1] || ""

  if (!base64WithoutHeader) {
    const slice = `${imgBase64 || ""}`.slice(0, 50)
    throw new Error(`couldn't process input image "${slice}..."`)
  }

  // Convert base64 to buffer
  const tmpBuffer = Buffer.from(base64WithoutHeader, 'base64')

  const newBuffer = await sharp(tmpBuffer)
    .png()
    .toBuffer()

  // Convert the buffer back to base64
  const newImageBase64 = newBuffer.toString('base64')

  return `data:image/png;base64,${newImageBase64}`
}