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, 52 insertions, 0 deletions

diff --git a/ui/presentation/Label.js b/ui/presentation/Label.js
new file mode 100644
index 0000000..81223df
--- /dev/null
+++ b/ui/presentation/Label.js
@@ -0,0 +1,52 @@
+import {DisplayElement} from 'tui-lib/ui/primitives'
+
+import * as ansi from 'tui-lib/util/ansi'
+
+export default class Label extends DisplayElement {
+  // A simple text display. Automatically adjusts size to fit text.
+
+  constructor(text = '') {
+    super()
+
+    this.text = text
+    this.textAttributes = []
+  }
+
+  fixLayout() {
+    this.w = ansi.measureColumns(this.text)
+  }
+
+  drawTo(writable) {
+    if (this.textAttributes.length) {
+      writable.write(ansi.setAttributes(this.textAttributes))
+    }
+
+    this.writeTextTo(writable)
+
+    if (this.textAttributes.length) {
+      writable.write(ansi.resetAttributes())
+    }
+
+    super.drawTo(writable)
+  }
+
+  writeTextTo(writable) {
+    writable.write(ansi.moveCursor(this.absTop, this.absLeft))
+    writable.write(this.text)
+  }
+
+  set text(newText) {
+    const ret = this.setDep('text', newText)
+    this.fixLayout()
+    return ret
+  }
+
+  get text() {
+    return this.getDep('text')
+  }
+
+  // Kinda bad, but works as long as you're overwriting the array instead of
+  // mutating it.
+  set textAttributes(val) { return this.setDep('textAttributes', val) }
+  get textAttributes() { return this.getDep('textAttributes') }
+}