use ESM module syntax & minor cleanups

The biggest change here is moving various element classes under
more scope-specific directories, which helps to avoid circular
dependencies and is just cleaner to navigate and expand in the
future.

Otherwise this is a largely uncritical port to ESM module syntax!
There are probably a number of changes and other cleanups that
remain much needed.

Whenever I make changes to tui-lib it's hard to believe it's
already been <INSERT COUNTING NUMBER HERE> years since the
previous time. First commits are from January 2017, and the
code originates a month earlier in KAaRMNoD!

1 files changed, 0 insertions, 80 deletions

diff --git a/ui/Element.js b/ui/Element.js
deleted file mode 100644
index c5beb59..0000000
--- a/ui/Element.js
+++ /dev/null
@@ -1,80 +0,0 @@
-const EventEmitter = require('events')
-
-module.exports = class Element extends EventEmitter {
-  // The basic class containing methods for working with an element hierarchy.
-  // Generally speaking, you usually want to extend DisplayElement instead of
-  // this class.
-
-  constructor() {
-    super()
-
-    this.children = []
-    this.parent = null
-  }
-
-  eachDescendant(fn) {
-    // Run a function on this element, all of its children, all of their
-    // children, etc.
-    fn(this)
-    for (const child of this.children) {
-      child.eachDescendant(fn)
-    }
-  }
-
-  addChild(child, afterIndex = this.children.length, {fixLayout = true} = {}) {
-    // TODO Don't let a direct ancestor of this be added as a child. Don't
-    // let itself be one of its childs either!
-
-    if (child === this) {
-      throw exception(
-        'EINVALIDHIERARCHY', 'An element cannot be a child of itself')
-    }
-
-    child.parent = this
-
-    if (afterIndex === this.children.length) {
-      this.children.push(child)
-    } else {
-      this.children.splice(afterIndex, 0, child)
-    }
-
-    if (fixLayout) {
-      child.fixLayout()
-    }
-  }
-
-  removeChild(child, {fixLayout = true} = {}) {
-    // Removes the given child element from the children list of this
-    // element. It won't be rendered in the future. If the given element
-    // isn't a direct child of this element, nothing will happen.
-
-    if (child.parent !== this) {
-      return
-    }
-
-    child.parent = null
-    this.children.splice(this.children.indexOf(child), 1)
-
-    if (fixLayout) {
-      this.fixLayout()
-    }
-  }
-
-  get root() {
-    let el = this
-    while (el.parent) {
-      el = el.parent
-    }
-    return el
-  }
-
-  get directAncestors() {
-    const ancestors = []
-    let el = this
-    while (el.parent) {
-      el = el.parent
-      ancestors.push(el)
-    }
-    return ancestors
-  }
-}