console-static-text

For the Rust crate, go to console_static_text.

Install:

# jsr
deno add jsr:@david/console-static-text

# npm
npm install console-static-text

Library for displaying text that should stay at the bottom of the console. This measures words to handle wrapping and has some console resizing support. Example use might be for displaying progress bars or rendering selections.

Example

import { staticText } from "console-static-text";
import { delay } from "@std/async/delay";

using scope = staticText.createScope();

scope.setText([
  "Some text",
  "Some very long text. ".repeat(10),
  () => `Time is: ${new Date()}`,
  (consoleSize) => `Console size: ${consoleSize.rows}, ${consoleSize.columns}`,
  () => {
    // or deferred and multiple lines.
    return [
      "Line 1",
      (consoleSize) => (Math.random() * consoleSize.columns!).toString(),
    ];
  },
]);
staticText.refresh(); // now draw to console window

await delay(1_000);
scope.logAbove("Hello!"); // this will be logged immediately above the other text

Render interval

You can start a render interval for the duration of some work:

import { renderInterval, staticText } from "console-static-text";
import { delay } from "@std/async/delay";

// defaults to 60
renderInterval.intervalMs = 30;

async function download() {
  using _renderScope = renderInterval.start(); // updates the displayed text periodically
  // make sure these are after so it's disposed before the render scope
  using timeScope = staticText.createScope();
  using downloadScope = staticText.createScope();
  const startTime = Date.now();
  timeScope.setText(() => `It's been ${Date.now() - startTime}ms`);
  for (let i = 0; i < 100; i++) {
    downloadScope.setText(`Downloading ${i}/100...`);
    await delay(30); // do some async work
  }
}

// will show the Downloading x/100... text for the duration
// of the function call and then clear the text on exit
await download();

Note this won't render if there's any blocking synchronous work. To do that, you must force a refresh via staticText.refresh().

Hanging indentation

Hanging indentation is possible by providing TextItem objects.

import { staticText } from "console-static-text";

using scope = staticText.createScope();

scope.setText([{
  text: "Some non-hanging text.",
}, {
  text: "Some long text that will wrap at a certain width.",
  hangingIndent: 4,
}]);

staticText.refresh(); // draw to console window

This is useful when implementing something like a selection UI where you want text to wrap with hanging indentation.

Singleton and instances

By default, the library has two exports that are singletons around stderr—staticText and renderInterval. These are an instance of StaticTextContainer and RenderInterval respectively. New instances of these classes can be created and used instead of the singletons if you wish.