如何精简并合并JS Cookie判断与获取函数？

Hey there! Let's clean up those cookie functions—they share almost identical logic, so merging them into a single, streamlined method makes perfect sense. Here's a polished, modern take that handles both checking existence and retrieving values:

Optimized Single Method #

function getCookie(cookieName, checkOnly = false) {
  // Split and clean up cookie string into valid key-value pairs
  const cookiePairs = document.cookie.split(';')
    .map(pair => pair.trim())
    .filter(pair => pair.length > 0);

  // Find the cookie matching our target name
  const matchingCookie = cookiePairs.find(pair => pair.startsWith(`${cookieName}=`));

  if (!matchingCookie) {
    return checkOnly ? false : null;
  }

  return checkOnly ? true : matchingCookie.split('=')[1];
}

Key Improvements & How to Use #

• Eliminated Duplication: No more repeating the cookie splitting/cleanup logic across two functions.
• Modern JS Syntax: Uses map, filter, and find for cleaner, more readable iteration (instead of clunky for loops).
• Flexible Behavior:
  • To check if a cookie exists: Call getCookie('yourCookieName', true) — returns true or false.
  • To retrieve the cookie's value: Call getCookie('yourCookieName') — returns the value (or null if it doesn't exist).
• Cleaner Trimming: Uses native trim() instead of a regex for removing whitespace (works in all modern browsers).

If you need to support super old browsers (like IE8), you can swap trim() with your original regex, and add a polyfill for Array.prototype.find—but for most projects today, this version is totally solid.

内容的提问来源于stack exchange，提问作者user1060990