8ee50178f3
Correct: `Array.from()` (it’s a static method) Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method) This patch uses the common `#` syntax to denote `.prototype.`.
23 lines
610 B
Markdown
23 lines
610 B
Markdown
### mapValues
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Creates an object with the same keys as the provided object and values generated by running the provided function for each value.
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Use `Object.keys(obj)` to iterate over the object's keys.
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Use `Array.prototype.reduce()` to create a new object with the same keys and mapped values using `fn`.
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```js
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const mapValues = (obj, fn) =>
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Object.keys(obj).reduce((acc, k) => {
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acc[k] = fn(obj[k], k, obj);
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return acc;
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}, {});
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```
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```js
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const users = {
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fred: { user: 'fred', age: 40 },
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pebbles: { user: 'pebbles', age: 1 }
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};
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mapValues(users, u => u.age); // { fred: 40, pebbles: 1 }
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```
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