js reg expression pick uppercase
const str = "HERE'S AN UPPERCASE PART of the string";
const upperCaseWords = str.match(/(\b[A-Z][A-Z]+|\b[A-Z]\b)/g);
// => [ 'HERE', 'S', 'AN', 'UPPERCASE', 'PART' ]
/*\b - start of the word
[A-Z] - Any character between capital A and Z
[A-Z]+ - Any character between capital A and Z,
but for one of more times and without interruption
| - OR
\b - start of the word
[A-Z] - Any character between capital A and Z
\b - end of the word
g - global (run multiple times till string ends,
not just for one instance)*/