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.`.
22 lines
580 B
Markdown
22 lines
580 B
Markdown
### extendHex
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Extends a 3-digit color code to a 6-digit color code.
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Use `Array.prototype.map()`, `String.prototype.split()` and `Array.prototype.join()` to join the mapped array for converting a 3-digit RGB notated hexadecimal color-code to the 6-digit form.
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`Array.prototype.slice()` is used to remove `#` from string start since it's added once.
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```js
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const extendHex = shortHex =>
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'#' +
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shortHex
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.slice(shortHex.startsWith('#') ? 1 : 0)
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.split('')
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.map(x => x + x)
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.join('');
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```
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```js
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extendHex('#03f'); // '#0033ff'
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extendHex('05a'); // '#0055aa'
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```
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