GitHub issue タブとシフトタブでスペース挿入 / tampermonkey

tampermonkey.js

// ==UserScript==
// @name         タブとシフトタブでスペース挿入
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  issue書く時にタブ使うと項目移動しちゃうので、無効にしてスペースが入るようになりました
// @author       @ma3tk
// @match        https://github.com/*
// @grant        none
// @see          https://qiita.com/n-ishida/items/da1cc0cfdaebe789d047
// @see          https://qiita.com/laineus/items/12a220d2ab086931232d
// ==/UserScript==

(function() {
  'use strict';
  const TAB_STR = '  ';

  const element = document.getElementById("issue_body");
  if (element) {
    element.addEventListener("keydown", inputTab);
  }

  function inputTab(e) {
    if (e.target.tagName !== 'TEXTAREA' || e.keyCode !== 9) return false;
    e.preventDefault();
    const selection = { left: e.target.selectionStart, right: e.target.selectionEnd };
    const lineStart = e.target.value.substr(0, selection.left).split('\n').length - 1;
    const lineEnd = e.target.value.substr(0, selection.right).split('\n').length - 1;
    const lines = e.target.value.split('\n');
    for (const i in lines) {
      if (i < lineStart || i > lineEnd || lines[i] === '') {
        continue;
      }
      if (!e.shiftKey) {
        // 行頭にタブ挿入
        lines[i] = TAB_STR + lines[i];
        selection.left += i == lineStart ? TAB_STR.length : 0;
        selection.right += TAB_STR.length;
      } else if (lines[i].substr(0, TAB_STR.length) === TAB_STR) {
        // 行頭のタブ削除
        lines[i] = lines[i].substr(TAB_STR.length);
        selection.left -= i == lineStart ? TAB_STR.length : 0;
        selection.right -= TAB_STR.length;
      }
    }
    e.target.value = lines.join('\n');
    e.target.setSelectionRange(selection.left, selection.right);

    return false;
  }
})();