camel case in javascript

1const sentence = 'The quick brown fox jumps over the lazy dog.';
2console.log(sentence.toUpperCase());
3// expected output: "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG."

1String.prototype.toCamelCase = function () {
2	let STR = this.toLowerCase()
3		.trim()
4		.split(/[ -_]/g)
5		.map(word => word.replace(word[0], word[0].toString().toUpperCase()))
6		.join('');
7	return STR.replace(STR[0], STR[0].toLowerCase());
8};