r3bl-ts-utils/src/tui-node-keyboard/readline-config.ts

The `r3bl-ts-utils` package is a set of useful TypeScript functions and classes that can be used in Node.js and browser environments. They are inspired by Kotlin stdlib, and Rust to write code as expressions rather than statements, colorized text, powerfu

/*
 * Copyright (c) 2022 R3BL LLC. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

import { _also } from "../lang-utils/kotlin-lang-utils"
import { Keypress } from "./keypress"
import { createMutableCopyOf } from "./keypress-builder-general"
import { KeyCreator } from "./keypress-constants"

/*
 * Unicode, UTF-8, JS, hex encoding:
 * - https://flaviocopes.com/javascript-unicode/
 * - https://dmitripavlutin.com/what-every-javascript-developer-should-know-about-unicode/#hexadecimal-escape-sequence
 * Unicode hex character to symbol (eg: '[' => '\x5b')
 * - https://www.utf8-chartable.de/
 * ASCII:
 * - https://www.ascii-code.com/
 *
 * Here's an example of a string generated when leftArrow is typed in the console: '\x1B[C'. Hex
 * escape sequence is the shortest form. Hex accept two digits (a hex number) after '\x' to
 * represent a single character. However, each character in the string is actually a hex number! In
 * order to translate the string into their numbers, we can use https://www.ascii-code.com/.
 *
 * Using these resources, we see that '\x1B[C' is broken down like so:
 * - '\x1' becomes '\x31'
 * - '\xB' becomes '\x42'
 * - '\x[' becomes '\x5B'
 * - '\xC' becomes '\x43'
 *
 * ENHANCEMENT: https://github.com/r3bl-org/r3bl-cmdr/issues/1
 */

/**
 * Note that the value of the map entry is a function that returns a copy of a key, so that there is
 * no chance of creating mutable constants that are shared publicly. The object that is returned is
 * meant to be modified (it is mutable) by other parts of the code.
 */
type InputToKeyPressDictionary = Map<string, () => Keypress>

export const keyCodeMap: InputToKeyPressDictionary = _also(
  new Map() as InputToKeyPressDictionary,
  (map) => {
    map
      .set("[D", () => createMutableCopyOf(KeyCreator.leftKey, undefined))
      .set("[C", () => createMutableCopyOf(KeyCreator.rightKey, undefined))
      .set("[A", () => createMutableCopyOf(KeyCreator.upKey, undefined))
      .set("[B", () => createMutableCopyOf(KeyCreator.downKey, undefined))
      .set("[6~", () => createMutableCopyOf(KeyCreator.pageDownKey, undefined))
      .set("[5~", () => createMutableCopyOf(KeyCreator.pageUpKey, undefined))
      .set("[H", () => createMutableCopyOf(KeyCreator.homeKey, undefined))
      .set("[F", () => createMutableCopyOf(KeyCreator.endKey, undefined))
  }
)

export const keyNameMap: InputToKeyPressDictionary = _also(
  new Map() as InputToKeyPressDictionary,
  (map) => {
    map
      .set("space", () => createMutableCopyOf(KeyCreator.spaceKey, undefined))
      .set("backspace", () => createMutableCopyOf(KeyCreator.backspaceKey, undefined))
      .set("delete", () => createMutableCopyOf(KeyCreator.deleteKey, undefined))
      .set("return", () => createMutableCopyOf(KeyCreator.returnKey, undefined))
      .set("tab", () => createMutableCopyOf(KeyCreator.tabKey, undefined))
      .set("escape", () => createMutableCopyOf(KeyCreator.escapeKey, undefined))
  }
)

export const keySequenceMap: InputToKeyPressDictionary = _also(
  new Map() as InputToKeyPressDictionary,
  (map) => {
    map
      .set("7F", () => createMutableCopyOf(KeyCreator.backspaceKey, undefined))
      .set("1B", () => createMutableCopyOf(KeyCreator.escapeKey, undefined))
      .set("[3~", () => createMutableCopyOf(KeyCreator.deleteKey, undefined))
      .set("\r", () => createMutableCopyOf(KeyCreator.returnKey, undefined))
      .set("\t", () => createMutableCopyOf(KeyCreator.tabKey, undefined))
  }
)

/**
 * This describes a keypress event that comes in from Node.js readline. The sequence, name, and code
 * properties are optional. Run the `npm run exp-node-readline-keypress-logger` script (which runs
 * readline-keypress-logger.ts in experimental) in order to see this in action.
 */
export interface ReadlineKey {
  sequence?: string
  name?: string
  code?: string
  ctrl: boolean
  meta: boolean
  shift: boolean
}