js string 统计

const str = "Hello, World!";
const charCount = str.length; // 13

function countSubstring(str, subStr) {
    return str.split(subStr).length - 1;
}

const str = "Hello, Hello, World!";
const subStrCount = countSubstring(str, "Hello"); // 2

function countWords(str) {
    return str.trim().split(/\s+/).length;
}

const str = "Hello, World! This is a test.";
const wordCount = countWords(str); // 6

function countUnicodeChars(str) {
    const regex = /[\s\S]/gu;
    let count = 0;
    while (regex.exec(str) !== null) {
        count++;
    }
    return count;
}

const str = "Hello, 🌍!";
const unicodeCharCount = countUnicodeChars(str); // 8