无需正则表达式，使用JavaScript验证逗号分隔的多个IP地址

Got it, let's build a regex-free solution to validate your comma-separated IP list. This approach will manually check each IP segment to ensure it meets the format and value requirements.

Step-by-Step Solution #

First, we'll split the input into individual IPs, then validate each one by breaking it down into its four segments and checking each segment's validity.

function validateIPList(input) {
    // Trim whitespace and split into individual IPs, filter out empty entries
    const ipList = input.trim().split(',').map(ip => ip.trim()).filter(ip => ip.length > 0);
    
    // Validate each IP in the list
    for (const ip of ipList) {
        if (!validateSingleIP(ip)) {
            return false;
        }
    }
    return true;
}

function validateSingleIP(ip) {
    const segments = ip.split('.');
    
    // Must have exactly 4 segments
    if (segments.length !== 4) {
        return false;
    }
    
    for (const segment of segments) {
        // Segment can't be empty or contain non-numeric characters
        if (segment.length === 0 || isNaN(Number(segment))) {
            return false;
        }
        
        const num = Number(segment);
        // Segment must be an integer between 0 and 255 inclusive
        if (!Number.isInteger(num) || num < 0 || num > 255) {
            return false;
        }
        
        // Optional: Disallow leading zeros (uncomment if needed)
        // if (segment.length > 1 && segment.startsWith('0')) {
        //     return false;
        // }
    }
    
    return true;
}

// Example usage:
const testInput = "1.1.1.1,2.2.2.2,3.3.3.,4.4.4.256";
console.log(validateIPList(testInput)); // Returns false (invalid segments in 3rd and 4th IPs)

How It Works #

• Input Handling: We first clean the input by trimming whitespace, splitting on commas, and removing any empty entries (from accidental extra commas).
• Single IP Validation:
  • Split the IP into 4 segments using the dot character. If there aren't exactly 4 segments, it's invalid.
  • For each segment:
    • Ensure it's not empty and contains only numeric characters.
    • Convert the segment to a number and check if it's an integer between 0 and 255.
    • Optional: Uncomment the leading zero check if you want to disallow IPs like 010.0.0.1 (though technically valid in IPv4, some systems prefer no leading zeros).

Testing the Function #

Using your example input "1.1.1.1,2.2.2.2,3.3.3.,4.4.4.256", the function will return false because:

• The third IP (3.3.3.) has an empty fourth segment.
• The fourth IP (4.4.4.256) has a segment value greater than 255.

内容的提问来源于stack exchange，提问作者tonyf