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.`.
14 lines
460 B
Markdown
14 lines
460 B
Markdown
### xProd
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Creates a new array out of the two supplied by creating each possible pair from the arrays.
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Use `Array.prototype.reduce()`, `Array.prototype.map()` and `Array.prototype.concat()` to produce every possible pair from the elements of the two arrays and save them in an array.
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```js
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const xProd = (a, b) => a.reduce((acc, x) => acc.concat(b.map(y => [x, y])), []);
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```
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```js
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xProd([1, 2], ['a', 'b']); // [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]
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```
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