621e1ff9c9
Almost works like GitHub * use Tab/Shift-Tab to indent/unindent the selected lines * use Enter to insert a new line with the same indentation and prefix
104 lines
3.7 KiB
JavaScript
104 lines
3.7 KiB
JavaScript
import {triggerEditorContentChanged} from './Paste.js';
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function handleIndentSelection(textarea, e) {
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const selStart = textarea.selectionStart;
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const selEnd = textarea.selectionEnd;
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if (selEnd === selStart) return; // do not process when no selection
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e.preventDefault();
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const lines = textarea.value.split('\n');
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const selectedLines = [];
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let pos = 0;
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for (let i = 0; i < lines.length; i++) {
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if (pos > selEnd) break;
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if (pos >= selStart) selectedLines.push(i);
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pos += lines[i].length + 1;
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}
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for (const i of selectedLines) {
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if (e.shiftKey) {
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lines[i] = lines[i].replace(/^(\t| {1,2})/, '');
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} else {
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lines[i] = ` ${lines[i]}`;
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}
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}
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// re-calculating the selection range
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let newSelStart, newSelEnd;
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pos = 0;
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for (let i = 0; i < lines.length; i++) {
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if (i === selectedLines[0]) {
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newSelStart = pos;
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}
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if (i === selectedLines[selectedLines.length - 1]) {
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newSelEnd = pos + lines[i].length;
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break;
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}
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pos += lines[i].length + 1;
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}
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textarea.value = lines.join('\n');
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textarea.setSelectionRange(newSelStart, newSelEnd);
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triggerEditorContentChanged(textarea);
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}
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function handleNewline(textarea, e) {
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const selStart = textarea.selectionStart;
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const selEnd = textarea.selectionEnd;
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if (selEnd !== selStart) return; // do not process when there is a selection
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const value = textarea.value;
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// find the current line
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// * if selStart is 0, lastIndexOf(..., -1) is the same as lastIndexOf(..., 0)
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// * if lastIndexOf reruns -1, lineStart is 0 and it is still correct.
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const lineStart = value.lastIndexOf('\n', selStart - 1) + 1;
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let lineEnd = value.indexOf('\n', selStart);
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lineEnd = lineEnd < 0 ? value.length : lineEnd;
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let line = value.slice(lineStart, lineEnd);
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if (!line) return; // if the line is empty, do nothing, let the browser handle it
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// parse the indention
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const indention = /^\s*/.exec(line)[0];
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line = line.slice(indention.length);
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// parse the prefixes: "1. ", "- ", "* ", "[ ] ", "[x] "
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// there must be a space after the prefix because none of "1.foo" / "-foo" is a list item
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const prefixMatch = /^([0-9]+\.|[-*]|\[ \]|\[x\])\s/.exec(line);
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let prefix = '';
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if (prefixMatch) {
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prefix = prefixMatch[0];
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if (lineStart + prefix.length > selStart) prefix = ''; // do not add new line if cursor is at prefix
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}
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line = line.slice(prefix.length);
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if (!indention && !prefix) return; // if no indention and no prefix, do nothing, let the browser handle it
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e.preventDefault();
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if (!line) {
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// clear current line if we only have i.e. '1. ' and the user presses enter again to finish creating a list
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textarea.value = value.slice(0, lineStart) + value.slice(lineEnd);
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} else {
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// start a new line with the same indention and prefix
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let newPrefix = prefix;
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if (newPrefix === '[x]') newPrefix = '[ ]';
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if (/^\d+\./.test(newPrefix)) newPrefix = `1. `; // a simple approach, otherwise it needs to parse the lines after the current line
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const newLine = `\n${indention}${newPrefix}`;
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textarea.value = value.slice(0, selStart) + newLine + value.slice(selEnd);
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textarea.setSelectionRange(selStart + newLine.length, selStart + newLine.length);
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}
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triggerEditorContentChanged(textarea);
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}
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export function initTextareaMarkdown(textarea) {
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textarea.addEventListener('keydown', (e) => {
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if (e.key === 'Tab' && !e.ctrlKey && !e.metaKey && !e.altKey) {
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// use Tab/Shift-Tab to indent/unindent the selected lines
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handleIndentSelection(textarea, e);
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} else if (e.key === 'Enter' && !e.shiftKey && !e.ctrlKey && !e.metaKey && !e.altKey) {
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// use Enter to insert a new line with the same indention and prefix
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handleNewline(textarea, e);
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}
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});
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}
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