vue-scrolling-table

> A Vue component to create tables with vertical and horizontal scrolling. Flexbox-based.

Demo

There is a live demo here:
https://tallent.us/vue-scrolling-table

The demo will allow you to play with various options.

The repo for the demo application is here:
https://github.com/richardtallent/vue-scrolling-table-sample

Intro

I recently needed a Vue component for a data grid in a desktop application I'm building. No need for
responsiveness--in this case, I just need one huge table that scrolls vertically and horizontally,
like a spreadsheet. I also needed the table to fit itself neatly into a flexbox layout, taking up
any available space.

"No problem, this is late 2017, we have modern browsers with CSS2 sticky!" Nope. Browser support
for sticky is still buggy and incomplete, and I also needed the solution to work on IE11 to support
outdated corporate environments.

I found some very nice datagrid components, but none that suported everything on my wish list:

- Flexbox sizing
- Horizontal and vertical scrolling body
- Flexibility to render my and cells however I want (which, for me, probably means
lots of custom renderers, many of which will probably be Vue components of their own).
- No built-in data model (I'd rather implement sorting, paging, etc. myself)
- English documentation (Vue has global popularity, which is awesome, but occasionally that means
some great components are out of reach.)

So, I wrote this component. It is purposefully bare-bones, only drawing the table elements and
synchronizing the horizontal scrolling of the header and body. It doesn't render any , ,
or elements itself. Instead, your parent component/application should render those using
named slots. This gives you complete control over how those are handled, and allows this component
to just focus on its sole task of making the table fit its parent and allowing the body to scroll.

If you're curious, before creating the Vue component, the proof of concept was done on CodePen:
https://codepen.io/richardtallent/pen/rpWBQK

Example Usage

In your main.js, if you want to globally register the component and its CSS:

``JavaScript
import VueScrollingTable from "vue-scrolling-table"
import "/node_modules/vue-scrolling-table/dist/style.css"
//...
createApp(App)
.component(VueScrollingTable.name, VueScrollingTable)
.mount("#app")
`

In your template:

`HTML




`

Properties

$3

This is a string value. The default is #CCC. This is the color used for the "dead area" within
any scrolling table that isn't used for the table contents. This dead area is possible because
the table fits its parent container, but the rows or columns may not fill the entire space. This
property accepts any legal CSS color expression (triplets, rgb(), etc.).

$3

Boolean, defaults to false. Set this to true if you are providing content for a tfoot slot,
otherwise the element will not be rendered.

$3

Boolean, defaults to true. Set to false if you _do not_ want your header to scroll automatically
when the user scrolls the body horizontally.

$3

Boolean, defaults to true. Set to false if you _do not_ want your footer to scroll automatically
when the user scrolls the body horizontally.

$3

Boolean, defaults to true. Set to false if you _do not_ want the user to be able to scroll the
body content horizontally (any overflow will be hidden).

$3

Boolean, defaults to true. Set to false if you _do not_ want the user to be able to scroll the
body content vertically (any overflow will be hidden).

Slots

To render your actual rows and cells, you'll be using _named slots_. This gives you full control
of how the table contents are rendered.

$3

Required. Use this slot to inject the element's contents. The component will freeze it at
the top, and will synchronize its horizontal scrolling with scroll (there may be a short
delay).

$3

Required. Use this slot to inject the element's contents. The component will make it
scrollable.

$3

Optional. Use this slot if you want to inject contents for a element. The component will
freeze it at the bottom, below the scrolled . For now, this element is not scrolled
automatically with the body. If you include this, you'll also need to set the includeFooter prop
to true so the component knows to render the element.

Events

A scroll event is emitted by this component when the user scrolls the body. This event passes
four arguments: the scrollTop, scrollLeft, scrollHeight, and scrollWidth. You
can use this to, for example, show icons indicating that the user can scroll (useful when the
browser doesn't display a scrollbar). Since this is fired based on the DOM scroll event, the
same usual caveat applies: this is a high-frequency event, so try not to do anything complicated
in response (if you need to do so, debounce the events and/or use requestAnimationFrame).

A header-dragover event is emitted as the user drags a draggable element around over the THEAD
element. This may be needed to, for example, implement resizable columns. The preventDefault
call is made automatically by this component.

A header-dragenter event is emitted when the user drags a draggable element into the THEAD
element. This may be needed to, for example, implement resizable columns.

A header-drop event is emitted when the user drops a draggable element on the THEAD element.
This may be needed to, for example, implement resizable columns.

Browser Compatibility

This component is compatible with modern browsers. It may be compatible with older browsers, but
I don't test on them.

Slot Markup and Styling Requirements

An important requirement of this component is that all and cells must have a
specific width set for them, either via CSS classes or style attributes. Cells can't auto-size
based on contents because that would leave the header and body cells with different widths.

While it's theoretically possible to update the header column widths to match the body and vice
versa, it's tricky, because unlike with scrolling, there are _many events_ that can result in a
table cell resize (content change, CSS change, window resize, layout resize, etc.). Most
implementations, including one I've done in the past, just end up polling on a timer and checking
for columns to resize.

You can implement this sort of column-width-tracking in your parent component if you want, but
otherwise, you'll need to set the width, min-width, and max-width for all and
cells to guarantee the width of all rows for a given column are the same. By default, they are
all set to 10em. While you can't use percentage units, depending on your layout, you can use
vw units to achieve a similar scaled effect.

Customizing the Style

What little default styling is provided on the table is purposefully _very_ basic, and is not
scoped, so it's easy to override in your calling application. Use table.scrolling as the base
selector.

How do I "freeze" a column?

Here's some sample CSS for freezing the first column in a table. Unfortunately, it only works
in Chrome and Safari as of December 2017:

`CSS
table.scrolling td:first-child,
table.scrolling th:first-child {
position: -webkit-sticky;
position: sticky;
left: 0;
}
`

Supporting this in every browser by simulating sticky is theoretically possible, but much
more difficult than the scrolling implemented by this component due to differences in row
height, etc. that would happen if the first column is removed from the normal flow to, say,
use absolute positioning and update the scroll position with Javascript.

Future plans

I plan to actually use this on an upcoming project at work. It will be a good torture-test
for the component. Some features I'm considering:

- [x] Emitting events when the tbody is scrolled, so the caller can do other things.
- [x] Optional footer scrolling.
- [ ] Get rid of the need for the includeFooter prop.
- [x] Option to disable/enable scrolling in either direction.
- [ ] Avoid creating extra block on right of header if browser doesn't show scroll bars.
- [x] Add TypeScript declarations (anyone know how to make Vite do this on build?)

I'm open to other ideas, as long as they don't limit the flexibility of using slots for
the header, body, and footer. But if someone wants to _build_ a data grid component that
has this as a dependency, I'm all for it.

Build Setup

`bash


install dependencies

npm install

build for production with minification

npm run build
`

Release History

| Date | Version | Notes |
| ---------- | ------- | ------------------------------------------------------------------------------------ |
| 2017.12.24 | 0.1.0 | First published version |
| 2017.12.24 | 0.1.1 | Patch based on sample app deveopment |
| 2017.12.24 | 0.1.2 | Fix: old version went to npm |
| 2017.12.25 | 0.2.0 | Added lots of options, updated README, fixed some display bugs when less data shown. |
| 2018.08-06 | 0.2.1 | Added header-dragenter, header-dragover, and header-drop` events. |
| 2018.08-06 | 0.2.2 | $emit. _sigh_ |
| 2020.02.02 | 1.0.0 | Upgraded to Vue 3, Vite, TypeScript. BREAKING, DO NOT UPGRADE FOR VUE 2.x. |
| 2020.02.02 | 1.0.1 | Fix CSS export? |
| 2020.02.05 | 1.0.3 | Gave up on TS. Fix CSS export? |
| 2020.02.10 | 1.0.4 | TS Fixed. CSS injection is not automatic for Vite, documented this. |
| 2020.02.10 | 2.0.0 | Simplify implementation (requires Vue 3.2). Border/BG styles easier to override. |