22 lines
577 B
Markdown
22 lines
577 B
Markdown
---
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title: "[].map(parseInt)"
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---
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## Fan fact
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`[0xa, 0xa, 0xa].map(parseInt)` results in `[10, NaN, 2]`.
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## Why???
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`parseInt(0xa, 0, [0xa, 0xa, 0xa])`
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The second argument is `0` so the first argument gonna be treated as decimal number becoming `10`.
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`parseInt(0xa, 1, [0xa, 0xa, 0xa])`
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The second argument is `1` which is invalid as a radix so the result ends up with `NaN`.
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`parseInt(0xa, 2, [0xa, 0xa, 0xa])`
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The second argument is `2` meaning the first argument going to be handled as a binary number. `0xa` is `10` in binary, which results in `2` in decimal form.
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