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@gragland gragland/use-media.jsx
Last active May 2, 2019

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import { useState, useEffect } from 'react';
function App() {
const columnCount = useMedia(
// Media queries
['(min-width: 1500px)', '(min-width: 1000px)', '(min-width: 600px)'],
// Column counts (relates to above media queries by array index)
[5, 4, 3],
// Default column count
2
);
// Create array of column heights (start at 0)
let columnHeights = new Array(columnCount).fill(0);
// Create array of arrays that will hold each column's items
let columns = new Array(columnCount).fill().map(() => []);
data.forEach(item => {
// Get index of shortest column
const shortColumnIndex = columnHeights.indexOf(Math.min(...columnHeights));
// Add item
columns[shortColumnIndex].push(item);
// Update height
columnHeights[shortColumnIndex] += item.height;
});
// Render columns and items
return (
<div className="App">
<div className="columns is-mobile">
{columns.map(column => (
<div className="column">
{column.map(item => (
<div
className="image-container"
style={{
// Size image container to aspect ratio of image
paddingTop: (item.height / item.width) * 100 + '%'
}}
>
<img src={item.image} alt="" />
</div>
))}
</div>
))}
</div>
</div>
);
}
// Hook
function useMedia(queries, values, defaultValue) {
// Array containing a media query list for each query
const mediaQueryLists = queries.map(q => window.matchMedia(q));
// Function that gets value based on matching media query
const getValue = () => {
// Get index of first media query that matches
const index = mediaQueryLists.findIndex(mql => mql.matches);
// Return related value or defaultValue if none
return typeof values[index] !== 'undefined' ? values[index] : defaultValue;
};
// State and setter for matched value
const [value, setValue] = useState(getValue);
useEffect(
() => {
// Event listener callback
// Note: By defining getValue outside of useEffect we ensure that it has ...
// ... current values of hook args (as this hook callback is created once on mount).
const handler = () => setValue(getValue);
// Set a listener for each media query with above handler as callback.
mediaQueryLists.forEach(mql => mql.addListener(handler));
// Remove listeners on cleanup
return () => mediaQueryLists.forEach(mql => mql.removeListener(handler));
},
[] // Empty array ensures effect is only run on mount and unmount
);
return value;
}
@ostgals

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commented Jan 25, 2019

I see two possible optimizations.

The first one allows to avoid unneed rerender each time the 'resize' event is fired by calling set only if value actually changed.
And the second will save some computations and memory allocation expences by memoizing matchMedia calls (matchMedia returns an instance of MediaQueryList which can be reused between renders).

Optimized sandbox: https://codesandbox.io/s/1vn230242l

@gragland

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commented Feb 11, 2019

@ostgals Thanks for the tips! I've actually changed this hook quite a bit. It now supports any media query, not just screen width. I think as a result the issues you pointed out are resolved, but let me know if any other suggestions (or issues with updated hook).

@rluiten

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commented Mar 1, 2019

This is a question about the styling, it seems to me it could be a bit simpler. I do not know how you arrived at this solution and it may be an artifact of a previous version, or maybe it behaves differently in some scenario I am not conscious of.

I noticed if I remove the inline style on .image-container (remove the padding-top) then remove all the styles for .image-container except leaving only margin-bottom it seems to be equivalent. Is this so?

Noticed something else trivial I believe the two identifiers columnHeights, and columns can be made const.

By the way love your https://usehooks.com/ site

@gragland

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commented Mar 27, 2019

@rluiten Yeah the stying is probably weird. Probably left-over from original source code I copied at https://codesandbox.io/s/26mjowzpr?from-embed. Generally, I just try to get the styling done as quickly as possible since the main focus is on the React hook recipe.. so don't go pushing my styling right to production :)

And glad you're liking the site!

@cbrannen9a

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commented Apr 30, 2019

The eslint exhaustive-deps rules have issues with useEffect not using dependencies think the below resolves that, does require use of useCallback hook as well now, hope this helps:

`

function useMedia(queries, values, defaultValue) {
// Array containing a media query list for each query
const mediaQueryLists = queries.map(q => window.matchMedia(q));

// Function that gets value based on matching media query
const getValue = useCallback(() => {
    // Get index of first media query that matches
    const index = mediaQueryLists.findIndex(mql => mql.matches);
    // Return related value or defaultValue if none
    return typeof values[index] !== 'undefined'
        ? values[index]
        : defaultValue;
}, [values, defaultValue, mediaQueryLists]);

// State and setter for matched value
const [value, setValue] = useState(getValue);

useEffect(() => {
    // Event listener callback
    // Note: By defining getValue outside of useEffect we ensure that it has ...
    // ... current values of hook args (as this hook callback is created once on mount).
    const handler = () => setValue(getValue);
    // Set a listener for each media query with above handler as callback.
    mediaQueryLists.forEach(mql => mql.addListener(handler));
    // Remove listeners on cleanup
    return () =>
        mediaQueryLists.forEach(mql => mql.removeListener(handler));
}, [getValue, mediaQueryLists]);

return value;

}

`

@NateRadebaugh

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commented May 2, 2019

Why does this not use useLayoutEffect since it is likely based on layout changes?

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