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 *
// @version 2.0.0
// @grant GM_addStyle
// ==/UserScript==
class Editor {
constructor(textarea) {
this.el = textarea;
}
getSelectionRange() {
return {
start: this.el.selectionStart,
end: this.el.selectionEnd
};
}
setSelectionRange(start, end) {
this.el.setSelectionRange(start, end);
}
getCaretPos(collapse = false) {
if (this.el.selectionDirection == "backward" || collapse) {
return this.el.selectionStart;
}
return this.el.selectionEnd;
}
setCaretPos(pos, collapse = false) {
if (collapse) {
this.setSelectionRange(pos, pos);
} else {
var start = this.el.selectionStart,
end = this.el.selectionEnd,
dir = this.el.selectionDirection;
if (dir == "backward") {
[start, end] = [end, start];
dir = "forward";
}
end = pos;
if (end < start) {
[start, end] = [end, start];
dir = "backward";
}
this.el.selectionEnd = end;
this.el.selectionStart = start;
this.el.selectionDirection = dir;
}
}
getLineRange(start, end) {
var content = this.getContent(),
i, j;
i = content.lastIndexOf("\n", start - 1) + 1;
if (content[end - 1] == "\n") {
j = end;
} else {
j = content.indexOf("\n", end) + 1;
if (j == 0) {
j = content.length;
}
}
return {
start: i,
end: j
};
}
getSelectionLineRange() {
var range = this.getSelectionRange();
return this.getLineRange(range.start, range.end);
}
getSelectionLine() {
var content = this.getContent(),
range = this.getSelectionLineRange();
return content.slice(range.start, range.end);
}
getCurrentLineRange() {
var pos = this.getCaretPos();
return this.getLineRange(pos, pos);
}
getCurrentLine() {
var range = this.getCurrentLineRange(),
content = this.getContent();
return content.slice(range.start, range.end);
}
getContent() {
return this.el.value;
}
getSelection() {
var content = this.getContent(),
range = this.getSelectionRange();
return content.slice(range.start, range.end);
}
setRangeText(...args) {
this.el.setRangeText(...args);
}
}
var braceMatch = {
"[": "]",
"{": "}",
"(": ")"
};
class Commands {
constructor(editor) {
this.editor = editor;
this.indentSize = 4;
this.indentChar = "\t";
}
sameLine() {
return !this.editor.getSelection().includes("\n");
}
betweenText() {
var line = this.editor.getSelectionLine(),
pos = this.editor.getCaretPos(),
lineRange = this.editor.getSelectionLineRange(),
match = line.match(/\S/);
if (!match) {
return false;
}
return pos >= lineRange.start + match.index;
}
getIndentInfo(text) {
var i, count = 0;
for (i = 0; i < text.length; i++) {
var c = text[i];
if (c == " ") {
count++;
} else if (c == "\t") {
count += 4;
} else {
break;
}
}
return {
count: Math.floor(count / this.indentSize),
length: i
};
}
indent() {
if (this.sameLine()) {
var range = this.editor.getSelectionLineRange(),
line = this.editor.getSelectionLine(),
indent = this.getIndentInfo(line),
pos = this.editor.getSelectionRange().start;
if (pos >= range.start + indent.length) {
this.editor.setRangeText(
this.indentChar,
pos,
pos,
"end"
);
} else {
this.editor.setRangeText(
this.indentChar.repeat(indent.count + 1),
range.start,
range.start + indent.length,
"end"
);
}
} else {
this.multiIndent();
}
return true;
}
multiIndent(diff = 1) {
var lines = this.editor.getSelectionLine().split("\n"),
range = this.editor.getSelectionLineRange();
lines = lines.map(line => {
if (!line) return line;
var indent = this.getIndentInfo(line),
count = indent.count + diff;
if (count < 0) count = 0;
return this.indentChar.repeat(count) + line.slice(indent.length);
}).join("\n");
this.editor.setRangeText(lines, range.start, range.end, "select");
}
unindent() {
if (this.sameLine()) {
var range = this.editor.getSelectionLineRange(),
line = this.editor.getSelectionLine(),
indent = this.getIndentInfo(line),
pos = this.editor.getCaretPos(true);
if (pos <= range.start + indent.length && indent.count) {
this.editor.setRangeText(
this.indentChar.repeat(indent.count - 1),
range.start,
range.start + indent.length,
"end"
);
} else if (line.slice(0, pos - range.start).endsWith(this.indentChar)) {
this.editor.setRangeText(
"", pos - this.indentChar.length, pos, "end"
);
}
} else {
this.multiIndent(-1);
}
return true;
}
smartHome(collapse = false) {
var line = this.editor.getCurrentLine(),
range = this.editor.getCurrentLineRange(),
pos = this.editor.getCaretPos(collapse) - range.start,
indent = this.getIndentInfo(line);
if (pos == indent.length) {
this.editor.setCaretPos(range.start, collapse);
} else {
this.editor.setCaretPos(range.start + indent.length, collapse);
}
return true;
}
newLineIndent() {
var content = this.editor.getContent(),
range = this.editor.getSelectionRange(),
line = this.editor.getSelectionLine(),
indent = this.getIndentInfo(line),
out = "\n", pos,
left = content[range.start - 1],
right = content[range.end];
if (/[\[{(]/.test(left)) {
out += this.indentChar.repeat(indent.count + 1);
} else {
out += line.slice(0, indent.length);
}
pos = range.start + out.length;
if (right == braceMatch[left]) {
out += "\n" + line.slice(0, indent.length);
}
this.editor.setRangeText(out);
this.editor.setSelectionRange(pos, pos);
return true;
}
completeBraces(left) {
var right = braceMatch[left];
if (!right) return false;
var text = this.editor.getSelection(),
range = this.editor.getSelectionRange();
this.editor.setRangeText(left + text + right, range.start, range.end);
this.editor.setSelectionRange(range.start + 1, range.start + 1 + text.length);
return true;
}
}
var ignoreClassList = ["CodeMirror", "ace_editor"];
function validArea(area) {
if (area.nodeName != "TEXTAREA") {
return false;
}
if (area.dataset.textareaPlus === "false") {
return false;
}
if (area.dataset.textareaPlus === "true") {
return true;
}
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) || e.ctrlKey || e.altKey) {
return;
}
if (e.defaultPrevented) {
return;
}
function commands() {
return new Commands(new Editor(e.target));
}
var result = false;
if (e.keyCode == 9) {
// tab
if (e.shiftKey) {
result = commands().unindent();
} else {
result = commands().indent();
}
} else if (e.keyCode == 13) {
// enter
result = commands().newLineIndent();
} else if (e.keyCode == 36) {
// home
result = commands().smartHome(!e.shiftKey);
} else if (braceMatch[e.key]) {
// braces
result = commands().completeBraces(e.key);
}
if (result) {
e.preventDefault();
}
});
GM_addStyle("textarea {tab-size: 4; -moz-tab-size: 4; -o-tab-size: 4;}");