57 lines
1.6 KiB
TypeScript
57 lines
1.6 KiB
TypeScript
export function initTextarea(editCallback: () => void, textarea: HTMLTextAreaElement) {
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textarea.addEventListener("input", () => editCallback());
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let keyTrap = true;
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textarea.addEventListener("keydown", e => {
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if (!e.altKey && !e.ctrlKey) {
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if (e.key === "Escape") {
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if (keyTrap) {
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e.preventDefault();
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keyTrap = false;
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}
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} else if (e.key === "Tab" && keyTrap) {
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e.preventDefault();
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const { selectionStart, selectionEnd } = textarea;
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if (e.shiftKey) {
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// remove indentation on all selected lines
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const lines = textarea.value.split("\n");
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function getLine(char: number) {
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let line = 0;
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for (let c = 0; ; line++) {
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c += lines[line].length;
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if (c > char) {
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break;
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}
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}
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return line;
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};
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const startLine = getLine(selectionStart);
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const endLine = getLine(selectionEnd);
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let newSelectionStart = selectionStart;
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let newSelectionEnd = selectionEnd;
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for (let i = startLine; i <= endLine; i++) {
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if (lines[i][0] === "\t") {
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lines[i] = lines[i].slice(1);
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if (i === startLine) {
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newSelectionStart--;
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}
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newSelectionEnd--;
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}
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}
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textarea.value = lines.join("\n");
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textarea.setSelectionRange(newSelectionStart, newSelectionEnd);
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} else {
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// add tab character
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textarea.value = `${textarea.value.slice(0, selectionStart)}\t${textarea.value.slice(
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selectionEnd,
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)}`;
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textarea.setSelectionRange(selectionStart + 1, selectionStart + 1);
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}
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editCallback();
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} else {
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keyTrap = false;
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}
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}
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});
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}
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