e8d9acae9a
Tried to reproduce the groupBy behaviour from the lodash lib. https://lodash.com/docs/4.17.4#groupBy
17 lines
694 B
Plaintext
17 lines
694 B
Plaintext
### Group by
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Passing an array of values, a function or a property name thats going to be run against each value in the array,
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returns an object where the keys are the mapped results and the values is an array of the original values that generated the same results.
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```js
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const groupBy = (values, fn) => {
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return (typeof fn === 'function' ? values.map(fn) : values.map((val) => val[fn]))
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.reduce((acc, val, i) => {
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acc[val] = acc[val] === undefined ? [values[i]] : acc[val].concat(values[i]);
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return acc;
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}, {});
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}
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// groupBy([6.1, 4.2, 6.3], Math.floor) -> {4: [4.2], 6: [6.1, 6.3]}
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// groupBy(['one', 'two', 'three'], 'length') -> {3: ['one', 'two'], 5: ['three']}
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```
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