How to return argument from second function-CodePudding

const getBunnyPosition = () => {
  MATRIX.forEach((row, rowID) => {
    row.forEach((column, columnID) => {
      if (column === 1) {
        setBunnyImgPosition(rowID, columnID);
      }  
    });
  });
};

how can i return the rowID and columnID wihtout calling function with arguments? i tried with destructor return {rowID,columnID} but i cant get the columnID,in this code i called the second function for get the the indexes but i need them for other functions too

CodePudding user response：

You can't do that with forEach. Use traditional for-loops:

const getBunnyPosition = () => {
  for (let rowID = 0; rowID < MATRIX.length; rowID  ) {
    const row = MATRIX[rowID];
    for (let columnID = 0; columnID < row.length; columnID  ) {
      const column = row[columnID];
      if (column === 1) {
        return {
          rowID,
          columnID,
        };
      }
    }
  }
};

CodePudding user response：

you can just set a variable declared outside the loops.

const getBunnyPosition = () => {
  let bunnyPosition;
  MATRIX.forEach((row, rowID) => {
    let columnId = row.indexOf(1);
    if (columnId != -1) {
      bunnyPosition = {rowId, columnId};
    }
  });
  return bunnyPosition;
};

The for loop solution in the other question is a little better because the outer loop stops when the bunny is found. But for an 8x8 matrix it's not really a significant difference.

CodePudding user response：

Don't use forEach for this, but for loops. Actually for the inner loop you can just use findIndex -- as it will break out the loop when it finds a match and return the columnID for it.

Secondly, the caller can use destructuring to get the two components of the pair that will be returned (assuming success):

const getBunnyPosition = () => {
  for (const [rowID, row] of Object.entries(MATRIX)) {
    const columnID = row.findIndex(column => column == 1);
    if (columnID > -1) return [rowID, columnID];
  }
};

const MATRIX = [
    [0, 0, 0, 0],
    [0, 0, 1, 0], // <-- here is the bunny
    [0, 0, 0, 0],
];

const [rowID, columnID] = getBunnyPosition() ?? [];

console.log(rowID, columnID);