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Operator precedence is not preserved

See original GitHub issue

Source:

:root {
    --fluid-min-width: 320;
    --fluid-max-width: 1140;
    --fluid-screen: 100vw;
    --fluid-bp: calc(
        (var(--fluid-screen) - ((var(--fluid-min-width) / 16) * 1rem)) /
        ((var(--fluid-max-width) / 16) - (var(--fluid-min-width) / 16))
    );
}

7.0.4 outputs:

:root {
    --fluid-min-width: 320;
    --fluid-max-width: 1140;
    --fluid-screen: 100vw;
    --fluid-bp: calc(
        (var(--fluid-screen) - var(--fluid-min-width) / 16 * 1rem) / 
        (var(--fluid-max-width) - var(--fluid-min-width)) / 16
    );
}

The output should instead be:

:root {
    --fluid-min-width: 320;
    --fluid-max-width: 1140;
    --fluid-screen: 100vw;
    --fluid-bp: calc(
        (var(--fluid-screen) - (var(--fluid-min-width) / 16) * 1rem)) / 
        ((var(--fluid-max-width) - var(--fluid-min-width)) / 16
    );
}

postcss-calc is removing the necessary parentheses and affecting the operator precedence.

Issue Analytics

State:
Created 3 years ago
Reactions:1
Comments:7 (2 by maintainers)

Top GitHub Comments

2reactions

bashercommented, Sep 21, 2020

I have same issue with 7.0.4 which comes with parcel@2.0.0-nightly.400.

I only spotted this today on production sites with our responsive iframe containers, where we set an inline HTML style attribute with correct iframe aspect ratio, and pass that to Sass to evaluate padding-top as per this CSS Tricks article:

<div class="responsive-media" style="--aspectRatio: 560/315;">
    <iframe width="560" height="315" ...></iframe>
</div>

.responsive-media {
    padding-top: calc(100% / (var(--aspectRatio)));
}

Output in DEV mode with Parcel start:

padding-top: calc(100% / (var(--aspectRatio)));

Output in PROD mode after with Parcel build:

padding-top: calc(100% / var(--aspectRatio));

1reaction

bashercommented, Feb 19, 2021

I’ve given up waiting for a fix for this.

I’m now using the new standard CSS aspect-ratio property in supported browsers, and a hardcoded padding-top hack without calc() for older browsers.