in src/cdk/drag-drop/directives/drag.ts [377:441]
private _syncInputs(ref: DragRef<CdkDrag<T>>) {
ref.beforeStarted.subscribe(() => {
if (!ref.isDragging()) {
const dir = this._dir;
const dragStartDelay = this.dragStartDelay;
const placeholder = this._placeholderTemplate
? {
template: this._placeholderTemplate.templateRef,
context: this._placeholderTemplate.data,
viewContainer: this._viewContainerRef,
}
: null;
const preview = this._previewTemplate
? {
template: this._previewTemplate.templateRef,
context: this._previewTemplate.data,
matchSize: this._previewTemplate.matchSize,
viewContainer: this._viewContainerRef,
}
: null;
ref.disabled = this.disabled;
ref.lockAxis = this.lockAxis;
ref.dragStartDelay =
typeof dragStartDelay === 'object' && dragStartDelay
? dragStartDelay
: coerceNumberProperty(dragStartDelay);
ref.constrainPosition = this.constrainPosition;
ref.previewClass = this.previewClass;
ref
.withBoundaryElement(this._getBoundaryElement())
.withPlaceholderTemplate(placeholder)
.withPreviewTemplate(preview)
.withPreviewContainer(this.previewContainer || 'global');
if (dir) {
ref.withDirection(dir.value);
}
}
});
// This only needs to be resolved once.
ref.beforeStarted.pipe(take(1)).subscribe(() => {
// If we managed to resolve a parent through DI, use it.
if (this._parentDrag) {
ref.withParent(this._parentDrag._dragRef);
return;
}
// Otherwise fall back to resolving the parent by looking up the DOM. This can happen if
// the item was projected into another item by something like `ngTemplateOutlet`.
let parent = this.element.nativeElement.parentElement;
while (parent) {
if (parent.classList.contains(DRAG_HOST_CLASS)) {
ref.withParent(
CdkDrag._dragInstances.find(drag => {
return drag.element.nativeElement === parent;
})?._dragRef || null,
);
break;
}
parent = parent.parentElement;
}
});
}