All files utils.js

100% Statements 45/45
100% Branches 16/16
100% Functions 14/14
100% Lines 40/40
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106  264x 264x         115x               9x 1x       8x 56x 56x 56x       8x 8x 56x 20x     20x                       20x       12x   56x           20x       2x     2x 14x 14x                 2x 2x 2x 6x 6x           2x 14x 42x 42x     14x 14x 14x     14x 42x 42x   14x 14x   2x    
export function round(value, decimals) {
  if (!decimals) decimals = 0;
  return Number(Math.round(value + 'e' + decimals) + 'e-' + decimals);
}
 
// return two decimal places rounded number
export function ratio({ width, height }) {
  return round(width / height, 2);
}
 
// takes the Gallery's photos array, width of the container,
// margin between photos Gallery prop, and columns Gallery prop.
// calculates, sizes based on columns and returns the photos array
// with new height/width props in each object
export function computeSizes({ photos, columns, width, margin }) {
  if (!width) {
    return [];
  }
  // divide photos over rows, max cells based on `columns`
  // effectively resulting in [[0, 1, 2], [3, 4, 5], [6, 7]]
  const rows = photos.reduce((acc, cell, idx) => {
    const row = Math.floor(idx / columns);
    acc[row] = acc[row] ? [...acc[row], cell] : [cell]; // eslint-disable-line no-param-reassign
    return acc;
  }, []);
  // calculate total ratio of each row, and adjust each cell height and width
  // accordingly.
  let ratios = [];
  const rowsWithSizes = rows.map((row, rowIndex) => {
    const totalRatio = row.reduce((result, photo) => result + ratio(photo), 0);
    const rowWidth = width - row.length * (margin * 2);
 
    // save total ratio of each row
    if (rowIndex !== rows.length - 1) ratios.push(totalRatio);
 
    // assign height
    // 3 scenarios...
    //  if its a regular row where row.length === columns
    //    rowWidth / totalRatio
    //  if columns > row.length
    //    if !lastRow
    //      use the average aspect ratio of previous rows
    //    else (all photos are on a single row)
    //      ...
    const height =
      row.length === columns
        ? rowWidth / totalRatio
        : photos.length < columns
          ? rowWidth / totalRatio * (row.length / columns)
          : rowWidth / (ratios.reduce((acc, item) => acc + item, 0) / (rows.length - 1));
 
    return row.map(photo => ({
      ...photo,
      height: round(height, 1),
      width: round(height * ratio(photo), 1),
    }));
  });
  return rowsWithSizes.reduce((acc, row) => [...acc, ...row], []);
}
export function computeSizesColumns({ photos, columns, width, margin }) {
  // calculate each colWidth based on total width and column amount
  let colWidth = (width - margin * 2 * columns) / columns;
 
  // map through each photo to assign adjusted height and width based on colWidth
  const photosWithSizes = photos.map(photo => {
    const newHeight = photo.height / photo.width * colWidth;
    return {
      ...photo,
      width: round(colWidth, 1),
      height: round(newHeight, 1),
    };
  });
 
  // store all possible left positions
  // and current top positions for each column
  const colLeftPositions = [];
  const colCurrTopPositions = [];
  for (var i = 0; i < columns; i++) {
    colLeftPositions[i] = round(i * (colWidth + margin * 2), 1);
    colCurrTopPositions[i] = 0;
  }
 
  // map through each photo, then reduce thru each "column"
  // find column with the smallest height and assign to photo's 'top'
  // update that column's height with this photo's height
  const photosPositioned = photosWithSizes.map(photo => {
    const smallestCol = colCurrTopPositions.reduce((acc, item, i) => {
      acc = item < colCurrTopPositions[acc] ? i : acc;
      return acc;
    }, 0);
 
    photo.top = colCurrTopPositions[smallestCol];
    photo.left = colLeftPositions[smallestCol];
    colCurrTopPositions[smallestCol] = colCurrTopPositions[smallestCol] + photo.height + margin * 2;
 
    // store the tallest col to use for gallery height because of abs positioned elements
    const tallestCol = colCurrTopPositions.reduce((acc, item, i) => {
      acc = item > colCurrTopPositions[acc] ? i : acc;
      return acc;
    }, 0);
    photo.containerHeight = colCurrTopPositions[tallestCol];
    return photo;
  });
  return photosPositioned;
}