Positioning autocomplete at the caret takes two kinds of updates
A textarea's bounding box is easy to measure. An autocomplete menu usually needs a different anchor: the insertion point inside it. Those positions diverge as soon as text wraps or the textarea scrolls. A menu anchored to the bottom of the element can be nowhere near the word the user is editing. I maintain Caret Geometry , an alpha-stage browser primitive for measuring that anchor. Here is how…
Measuring the caret's position within a textarea is a relatively straightforward task. However, determining the optimal position for an autocomplete menu can prove more challenging. This is particularly true when the menu anchor diverges from the caret's location due to text wrapping or textarea scrolling. To address this, I utilized a browser primitive called Caret Geometry, which provides a means of measuring the caret's anchor.
By importing the getCaretRect function from the caret-geometry library, I was able to obtain the caret's position as a rectangle in viewport-relative CSS pixels. This rectangle is useful for determining where to place the autocomplete menu, as it accurately reflects the caret's position at any given moment.
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