1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
export function triggerEditorContentChanged(target) {
target.dispatchEvent(new CustomEvent('ce-editor-content-changed', {bubbles: true}));
}
function handleIndentSelection(textarea, e) {
const selStart = textarea.selectionStart;
const selEnd = textarea.selectionEnd;
if (selEnd === selStart) return; // do not process when no selection
e.preventDefault();
const lines = textarea.value.split('\n');
const selectedLines = [];
let pos = 0;
for (let i = 0; i < lines.length; i++) {
if (pos > selEnd) break;
if (pos >= selStart) selectedLines.push(i);
pos += lines[i].length + 1;
}
for (const i of selectedLines) {
if (e.shiftKey) {
lines[i] = lines[i].replace(/^(\t| {1,2})/, '');
} else {
lines[i] = ` ${lines[i]}`;
}
}
// re-calculating the selection range
let newSelStart, newSelEnd;
pos = 0;
for (let i = 0; i < lines.length; i++) {
if (i === selectedLines[0]) {
newSelStart = pos;
}
if (i === selectedLines[selectedLines.length - 1]) {
newSelEnd = pos + lines[i].length;
break;
}
pos += lines[i].length + 1;
}
textarea.value = lines.join('\n');
textarea.setSelectionRange(newSelStart, newSelEnd);
triggerEditorContentChanged(textarea);
}
function handleNewline(textarea, e) {
const selStart = textarea.selectionStart;
const selEnd = textarea.selectionEnd;
if (selEnd !== selStart) return; // do not process when there is a selection
const value = textarea.value;
// find the current line
// * if selStart is 0, lastIndexOf(..., -1) is the same as lastIndexOf(..., 0)
// * if lastIndexOf reruns -1, lineStart is 0 and it is still correct.
const lineStart = value.lastIndexOf('\n', selStart - 1) + 1;
let lineEnd = value.indexOf('\n', selStart);
lineEnd = lineEnd < 0 ? value.length : lineEnd;
let line = value.slice(lineStart, lineEnd);
if (!line) return; // if the line is empty, do nothing, let the browser handle it
// parse the indention
const indention = /^\s*/.exec(line)[0];
line = line.slice(indention.length);
// parse the prefixes: "1. ", "- ", "* ", "[ ] ", "[x] "
// there must be a space after the prefix because none of "1.foo" / "-foo" is a list item
const prefixMatch = /^([0-9]+\.|[-*]|\[ \]|\[x\])\s/.exec(line);
let prefix = '';
if (prefixMatch) {
prefix = prefixMatch[0];
if (lineStart + prefix.length > selStart) prefix = ''; // do not add new line if cursor is at prefix
}
line = line.slice(prefix.length);
if (!indention && !prefix) return; // if no indention and no prefix, do nothing, let the browser handle it
e.preventDefault();
if (!line) {
// clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
textarea.value = value.slice(0, lineStart) + value.slice(lineEnd);
} else {
// start a new line with the same indention and prefix
let newPrefix = prefix;
if (newPrefix === '[x]') newPrefix = '[ ]';
if (/^\d+\./.test(newPrefix)) newPrefix = `1. `; // a simple approach, otherwise it needs to parse the lines after the current line
const newLine = `\n${indention}${newPrefix}`;
textarea.value = value.slice(0, selStart) + newLine + value.slice(selEnd);
textarea.setSelectionRange(selStart + newLine.length, selStart + newLine.length);
}
triggerEditorContentChanged(textarea);
}
export function initTextareaMarkdown(textarea) {
textarea.addEventListener('keydown', (e) => {
if (e.key === 'Tab' && !e.ctrlKey && !e.metaKey && !e.altKey) {
// use Tab/Shift-Tab to indent/unindent the selected lines
handleIndentSelection(textarea, e);
} else if (e.key === 'Enter' && !e.shiftKey && !e.ctrlKey && !e.metaKey && !e.altKey) {
// use Enter to insert a new line with the same indention and prefix
handleNewline(textarea, e);
}
});
}
|
