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Merge getNearestBlockIndex and getDropTargetIndexAndOperation
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kevin940726 committed Oct 13, 2022
1 parent 3fef816 commit 9216c4b
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157 changes: 77 additions & 80 deletions packages/block-editor/src/components/use-block-drop-zone/index.js
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ import {
__experimentalUseDropZone as useDropZone,
} from '@wordpress/compose';
import { isRTL } from '@wordpress/i18n';
import { isUnmodifiedDefaultBlock } from '@wordpress/blocks';
import { isUnmodifiedDefaultBlock as getIsUnmodifiedDefaultBlock } from '@wordpress/blocks';

/**
* Internal dependencies
Expand Down Expand Up @@ -36,79 +36,75 @@ import { store as blockEditorStore } from '../../store';
*/

/**
* Given a list of block DOM elements finds the index that a block should be dropped
* at.
* @typedef {Object} WPBlockData
* @property {boolean} isUnmodifiedDefaultBlock Is the block unmodified default block.
* @property {() => DOMRect} getBoundingClientRect Get the bounding client rect of the block.
* @property {number} blockIndex The index of the block.
*/

/**
* Get the drop target position from a given drop point and the orientation.
*
* @param {Element[]} elements Array of DOM elements that represent each block in a block list.
* @param {WPBlockData[]} blocksData The block data list.
* @param {WPPoint} position The position of the item being dragged.
* @param {WPBlockListOrientation} orientation The orientation of a block list.
*
* @return {[number|undefined, WPInsertPosition]} The block index and the position that's closest to the drag position.
* @param {WPBlockListOrientation} orientation The orientation of the block list.
* @return {[number, WPDropOperation]} The drop target position.
*/
export function getNearestBlockIndex( elements, position, orientation ) {
export function getDropTargetPosition(
blocksData,
position,
orientation = 'vertical'
) {
const allowedEdges =
orientation === 'horizontal'
? [ 'left', 'right' ]
: [ 'top', 'bottom' ];

const isRightToLeft = isRTL();

let candidateIndex;
let candidatePosition = 'after';
let candidateDistance;

elements.forEach( ( element, index ) => {
const rect = element.getBoundingClientRect();

let [ distance, edge ] = getDistanceToNearestEdge(
position,
rect,
allowedEdges
);
// Prioritize the element if the point is inside of it.
if ( isPointContainedByRect( position, rect ) ) {
distance = 0;
}
let nearestIndex = 0;
let insertPosition = 'before';
let minDistance = Infinity;

if ( candidateDistance === undefined || distance < candidateDistance ) {
// Where the dropped block will be inserted on the nearest block.
candidatePosition =
edge === 'bottom' ||
( ! isRightToLeft && edge === 'right' ) ||
( isRightToLeft && edge === 'left' )
? 'after'
: 'before';

// Update the currently known best candidate.
candidateDistance = distance;
candidateIndex = index;
}
} );
blocksData.forEach(
( { isUnmodifiedDefaultBlock, getBoundingClientRect, blockIndex } ) => {
const rect = getBoundingClientRect();

return [ candidateIndex, candidatePosition ];
}
let [ distance, edge ] = getDistanceToNearestEdge(
position,
rect,
allowedEdges
);
// Prioritize the element if the point is inside of an unmodified default block.
if (
isUnmodifiedDefaultBlock &&
isPointContainedByRect( position, rect )
) {
distance = 0;
}

if ( distance < minDistance ) {
// Where the dropped block will be inserted on the nearest block.
insertPosition =
edge === 'bottom' ||
( ! isRightToLeft && edge === 'right' ) ||
( isRightToLeft && edge === 'left' )
? 'after'
: 'before';

// Update the currently known best candidate.
minDistance = distance;
nearestIndex = blockIndex;
}
}
);

/**
* Get the drop target index and operation based on the the blocks and the nearst block index.
*
* @param {number|undefined} nearestIndex The nearest block index calculated by getNearestBlockIndex.
* @param {WPInsertPosition} insertPosition Whether to insert before or after the nearestIndex.
* @param {WPBlock[]} blocks The blocks list.
* @return {[number, WPDropOperation]} The drop target.
*/
export function getDropTargetIndexAndOperation(
nearestIndex,
insertPosition,
blocks
) {
const adjacentIndex =
nearestIndex + ( insertPosition === 'after' ? 1 : -1 );
const nearestBlock = blocks[ nearestIndex ];
const adjacentBlock = blocks[ adjacentIndex ];
const isNearestBlockUnmodifiedDefaultBlock =
!! nearestBlock && isUnmodifiedDefaultBlock( nearestBlock );
!! blocksData[ nearestIndex ]?.isUnmodifiedDefaultBlock;
const isAdjacentBlockUnmodifiedDefaultBlock =
!! adjacentBlock && isUnmodifiedDefaultBlock( adjacentBlock );
!! blocksData[ adjacentIndex ]?.isUnmodifiedDefaultBlock;

// If both blocks are not unmodified default blocks then just insert between them.
if (
Expand Down Expand Up @@ -170,7 +166,8 @@ export default function useBlockDropZone( {
[ targetRootClientId ]
);

const { getBlockListSettings, getBlocks } = useSelect( blockEditorStore );
const { getBlockListSettings, getBlocks, getBlockIndex } =
useSelect( blockEditorStore );
const { showInsertionPoint, hideInsertionPoint } =
useDispatch( blockEditorStore );

Expand All @@ -179,37 +176,37 @@ export default function useBlockDropZone( {
} );
const throttled = useThrottle(
useCallback(
( event, currentTarget ) => {
const blockElements = Array.from(
currentTarget.children
).filter(
// Ensure the element is a block. It should have the `wp-block` class.
( element ) => element.classList.contains( 'wp-block' )
);
( event, ownerDocument ) => {
const blocks = getBlocks( targetRootClientId );

// The block list is empty, don't show the insertion point but still allow dropping.
if ( blockElements.length === 0 ) {
if ( blocks.length === 0 ) {
setDropTarget( {
index: 0,
operation: 'insert',
} );
return;
}

const [ nearestBlockIndex, insertPosition ] =
getNearestBlockIndex(
blockElements,
{ x: event.clientX, y: event.clientY },
getBlockListSettings( targetRootClientId )?.orientation
);
const blocksData = blocks.map( ( block ) => {
const clientId = block.clientId;

return {
isUnmodifiedDefaultBlock:
getIsUnmodifiedDefaultBlock( block ),
getBoundingClientRect: () =>
ownerDocument
.getElementById( `block-${ clientId }` )
.getBoundingClientRect(),
blockIndex: getBlockIndex( clientId ),
};
} );

const blocks = getBlocks( targetRootClientId );
const [ targetIndex, operation ] =
getDropTargetIndexAndOperation(
nearestBlockIndex,
insertPosition,
blocks
);
const [ targetIndex, operation ] = getDropTargetPosition(
blocksData,
{ x: event.clientX, y: event.clientY },
getBlockListSettings( targetRootClientId )?.orientation
);

setDropTarget( {
index: targetIndex,
Expand All @@ -231,7 +228,7 @@ export default function useBlockDropZone( {
// `currentTarget` is only available while the event is being
// handled, so get it now and pass it to the thottled function.
// https://developer.mozilla.org/en-US/docs/Web/API/Event/currentTarget
throttled( event, event.currentTarget );
throttled( event, event.currentTarget.ownerDocument );
},
onDragLeave() {
throttled.cancel();
Expand Down
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