AI solution for JavaScript Coding Question on BFE.dev
174. CSS Grid Layout auto-placement algorithm - sparse

Here's one possible solution to the problem:

type Grid = Array<Array<number>>type Item = {  id: number,  style?: {    gridRowStart?: number | string,    gridRowEnd?: number | string,    gridColumnStart?: number | string    gridColumnEnd?: number | string  }}function layout(rows: number, columns: number, items: Array<Item>): Grid {  const grid: Grid = Array.from({ length: rows }, () => Array.from({ length: columns }, () => 0))  let row = 1  let col = 1  for (const item of items) {    if (item.style?.gridRowStart && typeof item.style.gridRowStart === 'number') {      row = item.style.gridRowStart    }    if (item.style?.gridColumnStart && typeof item.style.gridColumnStart === 'number') {      col = item.style.gridColumnStart    }    const width = item.style?.gridColumnEnd      ? getSpan(item.style.gridColumnEnd) - col + 1      : 1    const height = item.style?.gridRowEnd      ? getSpan(item.style.gridRowEnd) - row + 1      : 1    for (let r = row; r < row + height; r++) {      for (let c = col; c < col + width; c++) {        grid[r-1][c-1] = item.id      }    }    col += width    if (col > columns) {      col = 1      row++    }  }  return grid}function getSpan(span: string): number {  const parts = span.split(' ')  if (parts.length !== 2 || parts[1] !== 'span') {    throw new Error(`Invalid grid span value: ${span}`)  }  const value = parseInt(parts[0], 10)  if (isNaN(value)) {    throw new Error(`Invalid grid span value: ${span}`)  }  return value}

Here's how it works:

• The layout function initializes an empty grid of the specified size and iterates through the list of items to place them in the grid.
• For each item, it extracts the gridRowStart, gridRowEnd, gridColumnStart, and gridColumnEnd values from its style field (if present), and uses them to compute the item's position and size in the grid.
• The item is then added to the grid by setting the corresponding cells to its id value.
• Finally, the function returns the completed grid.

Note that the function assumes that all items have valid, non-overlapping positions within the grid. If this is not the case, the results may be incorrect.