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.`.
17 lines
326 B
Markdown
17 lines
326 B
Markdown
### isUpperCase
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Checks if a string is upper case.
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Convert the given string to upper case, using `String.prototype.toUpperCase()` and compare it to the original.
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```js
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const isUpperCase = str => str === str.toUpperCase();
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```
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```js
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isUpperCase('ABC'); // true
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isLowerCase('A3@$'); // true
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isLowerCase('aB4'); // false
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```
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