How to Create a Masked Input for All IPv4 format Addresses in React?

It looks like we need to handle the masking differently to ensure that the placeholders remain visible while editing. We can use a more sophisticated approach by maintaining separate states for the display value and the actual value, and updating them appropriately on various events.

Here's a revised version of the IpAddressInput component:

import React, { useState, useRef } from 'react';

const isIpv4 = (ip) => {
	const rgx = /^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
	return rgx.test(ip);
};

const formatIp = (ip) => {
	const parts = ip.split('.').map(part => part.padEnd(3, '_'));
	return parts.join('.');
};

const IpAddressInput = () => {
	const [value, setValue] = useState('');
	const [displayValue, setDisplayValue] = useState('___ . ___ . ___ . ___');
	const inputRef = useRef(null);

	const handleFocus = () => {
		if (displayValue === '___ . ___ . ___ . ___') {
			setDisplayValue('');
		} else {
			setDisplayValue(value);
		}
	};

	const handleBlur = () => {
		if (!isIpv4(value.replace(/_/g, '0'))) {
			setDisplayValue('___ . ___ . ___ . ___');
			setValue('');
		} else {
			setDisplayValue(formatIp(value));
		}
	};

	const handleChange = (e) => {
		let newValue = e.target.value.replace(/[^0-9.]/g, '');
		const parts = newValue.split('.').map(part => part.padEnd(3, '_')).join('.');
		setValue(newValue);
		setDisplayValue(parts.slice(0, 15));
	};

	return (
		
	);
};

export default IpAddressInput;

Explanation

1. Separate value and displayValue States:

   • value holds the actual input value (e.g., 192.168.0.1).
   • displayValue holds the masked value (e.g., 192.168.0.1 or 192._ .___.___).

2. handleFocus Function:

   • Shows the actual input value without padding when the input field is focused.

3. handleBlur Function:

   • Validates the input and updates the display value to show the mask if the input is invalid.
   • If the input is valid, it formats the value with padding.

4. handleChange Function:

   • Cleans the input to allow only numbers and dots.
   • Updates both the actual value and the display value to maintain the mask.

This approach ensures that the mask remains visible while allowing users to input and edit valid IPv4 addresses.

not working..as soon as i focused text box - disappering and behaves like a normal text box without any mask

import React, { useState, useRef } from 'react';

const isIpv4 = (ip) => {
	const rgx = /^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
	return rgx.test(ip);
};

const formatIp = (ip) => {
	const parts = ip.split('.').map(part => part.padEnd(3, '_'));
	return parts.join('.');
};

const IpAddressInput = () => {
	const [value, setValue] = useState('___ . ___ . ___ . ___');
	const inputRef = useRef(null);

	const handleFocus = () => {
		if (value === '___ . ___ . ___ . ___') {
			setValue('');
		}
	};

	const handleBlur = () => {
		const formattedValue = value.replace(/_/g, '0');
		if (!isIpv4(formattedValue)) {
			setValue('___ . ___ . ___ . ___');
		} else {
			setValue(formatIp(formattedValue));
		}
	};

	const handleChange = (e) => {
		let newValue = e.target.value.replace(/[^0-9.]/g, '');
		const parts = newValue.split('.').map(part => part.padEnd(3, '_')).join('.');
		setValue(parts.slice(0, 15));
	};

	return (
		
	);
};

export default IpAddressInput;

• Ensure the mask is partially visible while editing: Instead of hiding the mask entirely, we can adjust the placeholder or formatting logic.
• Restrict input to valid characters and length: Use validation to prevent invalid characters and ensure the correct format.
• Allow users to input valid IPv4 addresses and edit them seamlessly: Handle input changes to allow correct editing and updating of individual parts.

Key Changes and Explanations

1. isIpv4 Function:

   • Ensures the validation pattern strictly matches IPv4 addresses.

2. formatIp Function:

   • Formats the IP address parts, padding them with underscores (_) to maintain the placeholder visibility while editing.

3. handleFocus Function:

   • Clears the input if it contains only the mask (___ . ___ . ___ . ___).

4. handleBlur Function:

   • Validates and formats the input when the input field loses focus. If the input is invalid, it reverts to the initial mask.

5. handleChange Function:

   • Cleans the input to allow only numbers and dots. It pads each part to ensure the mask remains visible while the user is editing.
   • Limits the total length to 15 characters to ensure a valid IPv4 format.

Additional Suggestions

• Consider using libraries such as react-input-mask for more complex masking and input handling.
• Make sure to add proper CSS styling to make the placeholders visually distinct from actual input values.
• Ensure the component handles edge cases gracefully, such as empty input or incomplete IP addresses.