redom/esm/unmount.js

Tiny turboboosted JavaScript library for creating user interfaces.

import { getEl } from "./util.js";
import { trigger } from "./mount.js";

export function unmount(parent, _child) {
  let child = _child;
  const parentEl = getEl(parent);
  const childEl = getEl(child);

  if (child === childEl && childEl.__redom_view) {
    // try to look up the view if not provided
    child = childEl.__redom_view;
  }

  if (childEl.parentNode) {
    doUnmount(child, childEl, parentEl);

    parentEl.removeChild(childEl);
  }

  return child;
}

export function doUnmount(child, childEl, parentEl) {
  const hooks = childEl.__redom_lifecycle;

  if (hooksAreEmpty(hooks)) {
    childEl.__redom_lifecycle = {};
    return;
  }

  let traverse = parentEl;

  if (childEl.__redom_mounted) {
    trigger(childEl, "onunmount");
  }

  while (traverse) {
    const parentHooks = traverse.__redom_lifecycle || {};

    for (const hook in hooks) {
      if (parentHooks[hook]) {
        parentHooks[hook] -= hooks[hook];
      }
    }

    if (hooksAreEmpty(parentHooks)) {
      traverse.__redom_lifecycle = null;
    }

    traverse = traverse.parentNode;
  }
}

function hooksAreEmpty(hooks) {
  if (hooks == null) {
    return true;
  }
  for (const key in hooks) {
    if (hooks[key]) {
      return false;
    }
  }
  return true;
}