Bug in SelectionModel single selection mode #10051
Description
Bug, feature request, or proposal:
Bug
What is the expected behavior?
Single selection mode with empty initial selection should work
What is the current behavior?
Single selection mode doesn't handle empty selection
What are the steps to reproduce?
Source code that constructs a single-select model:
initialSelection = [];
allowMultiSelect = false;
selection = new SelectionModel(
this.allowMultiSelect, this.initialSelection);
What is the use-case or motivation for changing an existing behavior?
This model doesn't handle the scenario where there's no selection at initialization (e.g. empty table) when it's single selection mode.
Which versions of Angular, Material, OS, TypeScript, browsers are affected?
Is there anything else we should know?
The problematic code is in SelectionModel's constructor...
constructor(
private _multiple = false,
initiallySelectedValues?: T[],
private _emitChanges = true) {
if (initiallySelectedValues && initiallySelectedValues.length) {
if (_multiple) {
initiallySelectedValues.forEach(value => this._markSelected(value));
} else {
this._markSelected(initiallySelectedValues[0]); // BUG - we need to handle initiallySelectedValues being empty....
}
// Clear the array in order to avoid firing the change event for preselected values.
this._selectedToEmit.length = 0;
}
}