export function patchMethod()

in packages/rum-core/src/common/patching/patch-utils.js [53:79]

• 20 lines of code
• 9 McCabe index (conditional complexity)

export function patchMethod(target, name, patchFn) {
  var proto = target
  while (proto && !proto.hasOwnProperty(name)) {
    proto = Object.getPrototypeOf(proto)
  }
  if (!proto && target[name]) {
    // somehow we did not find it, but we can see it. This happens on IE for Window properties.
    proto = target
  }

  const delegateName = apmSymbol(name)
  var delegate
  if (proto && !(delegate = proto[delegateName])) {
    delegate = proto[delegateName] = proto[name]
    // check whether proto[name] is writable
    // some property is readonly in safari, such as HtmlCanvasElement.prototype.toBlob
    const desc = proto && Object.getOwnPropertyDescriptor(proto, name)
    if (isPropertyWritable(desc)) {
      const patchDelegate = patchFn(delegate, delegateName, name)
      proto[name] = function () {
        return patchDelegate(this, arguments)
      }
      attachOriginToPatched(proto[name], delegate)
    }
  }
  return delegate
}