Test suite fail with MinHeap

[SBolivarLoL]

When I run the npx jest Heap one test suite fails and says:
error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.

12     delete(): number {
                 ~~~~~~

Test Suites: 1 failed, 1 total

I can't find the error and every function that has to return a value returns a value. And delete is not even on line 12.

This is my code:

export default class MinHeap {
  public length: number;
  private data: number[];


  constructor() {
    this.data = [];
    this.length = 0;
  }

  insert(value: number): void {
    this.data[this.length] = value;
    this.heapifyUp(this.length);
    this.length++;
  }

  delete(): number {
    if (this.length === 0) {
      return -1;
    }

    const out = this.data[0];
    this.length--;

    if (this.length === 0) {
      this.data = [];
      return out;
    }

    this.data[0] = this.data[this.length];
    this.heapifyDown(0);
    return out;
  }

  private heapifyDown(idx: number): void {
    const Lidx = this.leftChild(idx);
    const Ridx = this.rightChild(idx);

    if (idx >= this.length || Lidx >= this.length) {
      return;
    }

    const lV = this.data[Lidx];
    const rV = this.data[Ridx];
    const v = this.data[idx];

    if (lV > rV && v > rV) {
      this.data[idx] = rV;
      this.data[Ridx] = v;
      this.heapifyDown(Ridx);
    } else if (rV > lV && v > lV) {
      this.data[idx] = lV;
      this.data[Lidx] = v;
      this.heapifyDown(Lidx);
    }
  }

  private heapifyUp(idx: number): void {
    if (idx === 0) {
      return;
    }

    const p = this.parent(idx);
    const parentV = this.data[p];
    const v = this.data[idx];

    if (parentV > v) {
      this.data[idx] = parentV;
      this.data[p] = v;
      this.heapifyUp(p)
    }
  }

  private parent(idx: number): number {
    return Math.floor((idx - 1) / 2);
  }

  private leftChild(idx: number): number {
    return idx * 2 + 1;
  }

  private rightChild(idx: number): number {
    return idx * 2 + 2;
  }
}

[maxrzaw]

Your implementation passed all the tests when I tested it.

Could jest be referencing a MinHeap file in another day?
This would happen if you edited the MinHeap file in a src/dayN directory where N is not the latest day and a freshly generated MinHeap.ts file exists in the latest day.