Function swap

packages/core/src/render3/list_reconciliation.ts:36–47

(index1: number, index2: number)

  // them explicitly allow clear expression of intent and potentially more performant
  // implementations
  swap(index1: number, index2: number): void {
    const startIdx = Math.min(index1, index2);
    const endIdx = Math.max(index1, index2);
    const endItem = this.detach(endIdx);
    if (endIdx - startIdx > 1) {
      const startItem = this.detach(startIdx);
      this.attach(startIdx, endItem);
      this.attach(endIdx, startItem);
    } else {
      this.attach(startIdx, endItem);
    }
  }
  move(prevIndex: number, newIdx: number): void {
    // For move operations, the detach code path is the same one used for removing
    // DOM nodes, which would trigger `animate.leave` bindings. We need to skip