detect-grid
v2.0.0
Published
Detect and mark grid cells for easy styling
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Detect Grid
Detect and mark grid cells for easy styling.
What does it do?
This package detects the rows and columns of a layout visually by comparing the offset from the top-left edge of the parent container. Each element is assigned a row and column index.
It will mark each detected cell with data attributes for easy targeting in CSS. This makes styling cells by index feasible even in flexbox or grid layouts where visual position doesn't always follow source order.
Installation
npm install detect-grid
Usage
Detect grid cells
Returns an array of rows and columns for further processing. Indices are zero-based.
import detectGrid from 'detect-grid'
const grid = document.querySelector('.grid')
const rows = detectGrid(grid)
rows.forEach((cols, rowIndex) => {
cols.forEach((cell, colIndex) => {
console.log(`Cell at row ${rowIndex} and col ${colIndex}`, cell.textContent)
})
})
Mark grid cells
Detects rows and columns and mark them with data attributes for CSS styling.
import { markGrid } from 'detect-grid'
const grid = document.querySelector('.grid')
markGrid(grid, { selector: '.cell' })
Before
<div class="grid">
<div>
<div class="cell"></div>
<div class="cell"></div>
</div>
<div>
<div class="cell"></div>
<div class="cell"></div>
</div>
</div>
After
:warning: While the
detectGrid
function returns zero-based arrays, the data attributes added bymarkGrid
start counting from1
to keep compatibility with CSS nth-child selectors.
<div class="grid">
<div>
<div class="cell" data-nth-row="1" data-nth-col="1" data-first-row data-first-col></div>
<div class="cell" data-nth-row="1" data-nth-col="2" data-first-row data-last-col></div>
</div>
<div>
<div class="cell" data-nth-row="2" data-nth-col="1" data-first-col></div>
<div class="cell" data-nth-row="2" data-nth-col="2" data-last-col></div>
</div>
<div>
<div class="cell" data-nth-row="2" data-nth-col="1" data-last-row data-first-col></div>
<div class="cell" data-nth-row="2" data-nth-col="2" data-last-row data-last-col></div>
</div>
</div>
CSS variables
Some visual effects like gradients require CSS custom properties for calculating the correct value for each row and cell. You can enable those behind an optional feature flag when marking grid cells:
markGrid(grid, { cssVariables: true })
You can now use the following CSS properties like --col-fraction
or --row-fraction
for calculating styles:
<div class="grid">
<div>
<div class="cell" style="--col-index: 0; --col-count: 3; --col-fraction: 0; --row-index: 0; --row-count: 2; --row-fraction: 0;"></div>
<div class="cell" style="--col-index: 1; --col-count: 3; --col-fraction: 0.5; --row-index: 0; --row-count: 2; --row-fraction: 0;"></div>
<div class="cell" style="--col-index: 2; --col-count: 3; --col-fraction: 1; --row-index: 0; --row-count: 2; --row-fraction: 0;"></div>
</div>
<div>
<div class="cell" style="--col-index: 0; --col-count: 3; --col-fraction: 0; --row-index: 1; --row-count: 2; --row-fraction: 1;"></div>
<div class="cell" style="--col-index: 1; --col-count: 3; --col-fraction: 0.5; --row-index: 1; --row-count: 2; --row-fraction: 1;"></div>
<div class="cell" style="--col-index: 2; --col-count: 3; --col-fraction: 1; --row-index: 1; --row-count: 2; --row-fraction: 1;"></div>
</div>
</div>
Options
Configure how cells are detected by passing an options object as second parameter.
const rows = detectGrid(grid, {
selector: '.cell',
align: 'bottom'
})
|Option|Description|Type/Options|Default|
|---|---|---|---|
|selector
|DOM selector to find grid cells|Selector string|Use direct childnodes|
|justify
|Horizontal alignment of measuring point|String: left
, center
, right
|left
|
|align
|Vertical alignment of measuring point|String: top
, center
, bottom
|top
|
|tolerance
|Tolerance to group rows/columns by|Number (px)|0
|