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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | import { useState } from 'react';
import useInterval from 'react-useinterval';
import difference from 'lodash/difference';
import values from 'lodash/values';
import { DROPDOWN_PALCEMENT_BL } from './constants';
function getDropDownCss(bindTo, placement) {
if (!bindTo.current) return null;
const rect = bindTo.current.getBoundingClientRect();
const top = rect.height + rect.top + 2;
switch (placement) {
case DROPDOWN_PALCEMENT_BL:
return {
left: rect.left,
top,
};
default:
return {
right: window.innerWidth - (rect.left + rect.width),
top,
};
}
}
export default (bindTo, placement) => {
const defaultState = getDropDownCss(bindTo, placement);
const [state, replaceState] = useState(defaultState);
function observeChanges() {
const nextState = getDropDownCss(bindTo, placement);
const diff = difference(values(nextState), values(state));
if (diff.length) replaceState(nextState);
}
useInterval(observeChanges, 32);
return state;
};
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