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/**
* Replaces the current selection (if any) with a new range, after
* it’s configured by the given function.
*
* See also: selectNodeContents
* Example:
*
* selectRangeWith(range => {
* range.selectNodeContents(foo);
* range.setStart(foo.childNodes[0], 3);
* range.setEnd(foo.childNodes[0], 5);
* });
*/
function selectRangeWith(fun) {
const selection = getSelection();
// Deselect any ranges that happen to be selected, to prevent the
// Selection#addRange call from ignoring our new range (see
// more details).
selection.removeAllRanges();
// Create and configure a range.
const range = document.createRange();
fun(range);
// Select our new range.
selection.addRange(range);
}
/**
* Replaces the current selection (if any) with a new range, spanning
* the contents of the given node.
*/
function selectNodeContents(node) {
const previousActive = document.activeElement;
selectRangeWith(range => range.selectNodeContents(node));
// If the selection update causes the node or an ancestor to be
// focused (Chromium 80+), unfocus it, to avoid any focus-related
// styling such as outlines.
if (document.activeElement != previousActive) {
document.activeElement.blur();
}
}
/**
* Tries to convince a UA with lazy spellcheck to check and highlight
* the contents of the given nodes (form fields or @contenteditables).
*
* Each node is focused then immediately unfocused. Both focus and
* selection can be used for this purpose, but only focus works for
* @contenteditables.
*/
function trySpellcheck(...nodes) {
// This is inherently a flaky test risk, but Chromium (as of 87)
// seems to cancel spellcheck on a node if it wasn’t the last one
// focused for “long enough” (though immediate unfocus is ok).
// Using requestAnimationFrame or setInterval(0) are usually not
// under “trySpellcheck strategy” for an example).
const interval = setInterval(() => {
if (nodes.length > 0) {
const node = nodes.shift();
node.focus();
node.blur();
} else {
clearInterval(interval);
}
}, 250);
}