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improve algorithm to reduce selection to text node + charactar offset

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this follows the documentation of {focus|anchor}{Offset|Node} better
and was causing problems for creating ranges from the document selection
when doing ctrl+A in firefox as the anchorNode/Offset was expressed
as childNodes from the editor root.
This commit is contained in:
Bruno Windels 2019-09-04 15:58:59 +02:00
parent 4691108a16
commit e0668e8517
1 changed files with 40 additions and 8 deletions
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48
src/editor/dom.js
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@ -45,15 +45,47 @@ export function getCaretOffsetAndText(editor, sel) {
return {caret: offset, text};
}
function getSelectionOffsetAndText(editor, selectionNode, selectionOffset) {
// sometimes selectionNode is an element, and then selectionOffset means
// the index of a child element ... - 1 🤷
if (selectionNode.nodeType === Node.ELEMENT_NODE && selectionOffset !== 0) {
selectionNode = selectionNode.childNodes[selectionOffset - 1];
selectionOffset = selectionNode.textContent.length;
function tryReduceSelectionToTextNode(selectionNode, selectionOffset) {
// if selectionNode is an element, the selected location comes after the selectionOffset-th child node,
// which can point past any childNode, in which case, the end of selectionNode is selected.
// we try to simplify this to point at a text node with the offset being
// a character offset within the text node
// Also see https://developer.mozilla.org/en-US/docs/Web/API/Selection
while (selectionNode && selectionNode.nodeType === Node.ELEMENT_NODE) {
const childNodeCount = selectionNode.childNodes.length;
if (childNodeCount) {
if (selectionOffset >= childNodeCount) {
selectionNode = selectionNode.lastChild;
if (selectionNode.nodeType === Node.TEXT_NODE) {
selectionOffset = selectionNode.textContent.length;
} else {
// this will select the last child node in the next iteration
selectionOffset = Number.MAX_SAFE_INTEGER;
}
} else {
selectionNode = selectionNode.childNodes[selectionOffset];
// this will select the first child node in the next iteration
selectionOffset = 0;
}
} else {
// here node won't be a text node,
// but characterOffset should be 0,
// this happens under some circumstances
// when the editor is empty.
// In this case characterOffset=0 is the right thing to do
break;
}
}
const {text, offsetToNode} = getTextAndOffsetToNode(editor, selectionNode);
const offset = getCaret(selectionNode, offsetToNode, selectionOffset);
return {
node: selectionNode,
characterOffset: selectionOffset,
};
}
function getSelectionOffsetAndText(editor, selectionNode, selectionOffset) {
const {node, characterOffset} = tryReduceSelectionToTextNode(selectionNode, selectionOffset);
const {text, offsetToNode} = getTextAndOffsetToNode(editor, node);
const offset = getCaret(node, offsetToNode, characterOffset);
return {offset, text};
}