An userscript to improve plain textarea for code editing.
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// ==UserScript==
// @name Textarea Plus
// @description An userscript to improve plain textarea for code editing.
// @namespace eight04.blogspot.com
// @include http*
// @version 1.1
// @grant GM_addStyle
// ==/UserScript==
"use strict";
var ignoreClassList = ["CodeMirror", "ace_editor"];
var textareaPlus = function(){
var editor = {
indent: indent,
unindent: unindent,
home: home,
selectHome: selectHome,
enter: enter
};
function selectionRange(data){
return data.pos[1] - data.pos[0];
}
function takeRange(data) {
if (data.pos[0] > data.pos[1]) {
return [data.pos[1], data.pos[0]];
}
return data.pos;
}
function insert(data, text){
var pos = takeRange(data);
data.text = data.text.substr(0, pos[0]) + text + data.text.substr(pos[1]);
data.pos[0] = pos[0] + text.length;
data.pos[1] = data.pos[0];
}
function del(data){
if (!selectionRange(data)) {
data.pos[1]++;
}
insert(data, "");
}
function getLineStart(data, pos){
if (pos == undefined) {
pos = data.pos[1];
}
if (data.text[pos] == "\n") {
pos--;
}
var s = data.text.lastIndexOf("\n", pos);
if (s < 0) {
return 0;
}
return s + 1;
}
function getLineEnd(data, pos){
if (pos == undefined) {
pos = data.pos[1];
}
var s = data.text.indexOf("\n", pos);
if (s < 0) {
return data.text.length;
}
return s;
}
function multiIndent(data){
var pos = takeRange(data);
var lineStart = getLineStart(data, pos[0]), lineEnd = getLineEnd(data, pos[1]);
var lines = data.text.substr(lineStart, lineEnd - lineStart);
lines = lines.split("\n");
for (var i = 0; i < lines.length; i++) {
lines[i] = "\t" + lines[i];
}
lines = lines.join("\n");
data.text = data.text.substr(0, lineStart) + lines + data.text.substr(lineEnd);
if (data.pos[0] > data.pos[1]) {
data.pos[1] = lineStart;
data.pos[0] = lineEnd + i;
} else {
data.pos[0] = lineStart;
data.pos[1] = lineEnd + i;
}
}
function inMultiLine(data) {
var pos = takeRange(data);
var s = data.text.indexOf("\n", pos[0]);
if (s < 0) {
return false;
}
return s < pos[1];
}
function indent(data){
if (!selectionRange(data)) {
insert(data, "\t");
if (data.pos[0] < getTextStart(data)) {
home(data);
}
} else {
if (inMultiLine(data)) {
multiIndent(data);
} else {
insert(data, "\t");
}
}
}
function multiUnindent(data){
var pos = takeRange(data);
var lineStart = getLineStart(data, pos[0]), lineEnd = getLineEnd(data, pos[1]);
var lines = data.text.substr(lineStart, lineEnd - lineStart);
lines = lines.split("\n");
var len = 0;
for (var i = 0; i < lines.length; i++) {
var m = lines[i].match(/^( {4}| {0,3}\t?)(.*)$/);
// console.log(m);
len += m[1].length;
lines[i] = m[2];
}
lines = lines.join("\n");
data.text = data.text.substr(0, lineStart) + lines + data.text.substr(lineEnd);
if (data.pos[0] > data.pos[1]) {
data.pos[1] = lineStart;
data.pos[0] = lineEnd - len;
} else {
data.pos[0] = lineStart;
data.pos[1] = lineEnd - len;
}
}
function backspace(data) {
if (selectionRange(data)) {
del(data);
} else if (data.pos[0] > 0) {
data.pos[0]--;
del(data);
}
}
function unindent(data) {
if (inMultiLine(data)) {
multiUnindent(data);
} else if (!selectionRange(data) && data.text[data.pos[0] - 1] == "\t") {
backspace(data);
} else {
multiUnindent(data);
home(data);
}
}
function searchFrom(text, re, pos) {
pos = pos || 0;
var t = text.substr(pos);
var s = t.search(re);
if (s < 0) {
return -1;
}
return s + pos;
}
function getTextStart(data, pos) {
var lineStart = getLineStart(data, pos);
pos = searchFrom(data.text, /[\S\n]/, lineStart);
if (pos < 0 || data.text[pos] == "\n") {
return getLineEnd(data);
}
return pos;
}
function isTextStart(data) {
return getTextStart(data) == data.pos[1];
}
function home(data) {
if (isTextStart(data)) {
data.pos[0] = getLineStart(data);
} else {
data.pos[0] = getTextStart(data);
}
data.pos[1] = data.pos[0];
}
function selectHome(data) {
var pos = data.pos[0];
home(data);
data.pos[0] = pos;
}
function getIndents(data) {
var pos = takeRange(data);
var lineStart = getLineStart(data, pos[0]);
var len;
var textStart = getTextStart(data, pos[0]);
// console.log(textStart);
if (textStart >= pos[0]) {
len = pos[0] - lineStart;
} else {
len = textStart - lineStart;
}
return data.text.substr(lineStart, len);
}
function enter(data) {
// console.log(data);
var indents = getIndents(data);
insert(data, "\n" + indents);
}
function init(node, command) {
var data = {
text: node.value,
pos: [node.selectionStart, node.selectionEnd]
}, t;
if (node.selectionDirection == "backward") {
t = data.pos[0];
data.pos[0] = data.pos[1];
data.pos[1] = t;
}
editor[command](data);
node.value = data.text;
if (data.pos[0] > data.pos[1]) {
node.setSelectionRange(data.pos[1], data.pos[0], "backward");
} else {
node.setSelectionRange(data.pos[0], data.pos[1], "forward");
}
}
return init;
}();
function validArea(area) {
if (area.nodeName != "TEXTAREA") {
return false;
}
if (area.dataset.textareaPlus === "false") {
return false;
}
if (area.dataset.textareaPlus === "true") {
return true;
}
// if (area.onkeydown) {
// area.dataset.textareaPlus = "false";
// return false;
// }
var node = area, i;
while ((node = node.parentNode) != document.body) {
for (i = 0; i < ignoreClassList.length; i++) {
if (node.classList.contains(ignoreClassList[i])) {
area.dataset.textareaPlus = "false";
return false;
}
}
}
area.dataset.textareaPlus = "true";
return true;
}
window.addEventListener("keydown", function(e){
if (!validArea(e.target)) {
return;
}
var command;
if (e.keyCode == 9 && !e.ctrlKey && !e.altKey) {
// tab
if (e.shiftKey) {
command = "unindent";
} else {
command = "indent";
}
} else if (e.keyCode == 13 && !e.ctrlKey && !e.altKey && !e.shiftKey) {
// enter
command = "enter";
} else if (e.keyCode == 36 && !e.ctrlKey && !e.altKey) {
// home
if (!e.shiftKey) {
command = "home";
} else {
command = "selectHome";
}
} else {
return;
}
e.preventDefault();
e.stopPropagation();
textareaPlus(e.target, command);
}, true);
GM_addStyle("textarea {tab-size: 4; -moz-tab-size: 4; -o-tab-size: 4;}");