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postcss-zindex

Reduce z-index values with PostCSS.

Install

With npm do:

npm install postcss-zindex --save

Example

Sometimes, you may introduce z-index values into your CSS that are larger than necessary, in order to improve your understanding of how each stack relates to the others. For example, you might have a modal overlay at 5000 and the dialog for it at 5500 - so that modal classes occupy the 5xxx space.

But in production, it is unnecessary to use such large values for z-index where smaller values would suffice. This module will reduce all z-index declarations whilst respecting your original intent; such that the overlay becomes 1 and the dialog becomes 2. For more examples, see the tests.

Input

.modal {
    z-index: 5000
}

.modal-overlay {
    z-index: 5500
}

Output

.modal {
    z-index: 1
}

.modal-overlay {
    z-index: 2
}

Note that this module does not attempt to normalize relative z-index values, such as -1; indeed, it will abort immediately when encountering these values as it cannot be sure that rebasing mixed positive & negative values will keep the stacking context intact. Be careful with using this module alongside JavaScript injected CSS; ideally you should have already extracted all of your stacking context into CSS.

API

zindex([options])

options

startIndex

Type: number Default: 1

Set this to any other positive integer if you want to override z-indices from other sources outside your control. For example if a third party widget has a maximum z-index of 99, you can set this to 100 and not have to worry about stacking conflicts.

Usage

See the PostCSS documentation for examples for your environment.

Contributing

Pull requests are welcome. If you add functionality, then please add unit tests to cover it.

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