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Range Check v2.0.3

npm version   Build Status

This is a simple module to validate IP address, check IP address version, check if IP is within a range.

This started out as range_check but it does much more than just checking ranges but since it's already got a large amount of downloads (37,115 downloads in the last month as of this writing) I'll keep the name the same even though I kinda want to change it to something better.


npm install range_check or yarn add range_check

You can then import the functions as needed or require the entire range_check package depending on your own projects configuration.

IP Functions

Check if IP is valid

console.log(isIP('')); //returns true or false

Check IP version


console.log(version('')); //returns 4
console.log(version('2001:4860:8006::62')); //returns 6
console.log(version('foo')); //returns 0 as invalid IP address


console.log(isV4('')); //true
console.log(isV4('foo')); //false
console.log(isV4('123::123')); //false


console.log(isV6('123::123')); //true
console.log(isV6('foo')); //false
console.log(isV6('')); //false

Range Functions

Check if range is valid

You can use isRange if you want to validate an entire range.

console.log(isRange('2001:db8::/32')); //true
console.log(isRange('')); // true
console.log(isRange('qwerty')); // false

Check if IP is within range

console.log(inRange('', '')); //returns true

console.log(inRange('', '')); //returns false

console.log(inRange('2001:db8:1234::1', '2001:db8::/32')); //returns true

You can also give a list of ranges

console.log(inRange('', ['', ''])); //returns true


This function is useful to get a consistent IP address such for storing it in a database or when searching in a database after being stored using this. So if a V6 address was sent compacted or not, or if you searched by either version this function would make sure you get a consistent IP address for both versions. Also the possibly of saving a few bytes.

If an V6 addressed is mapped as v4 is given it will convert it to V4, If any other V6 address is given it is abbreviated and plain V4 addresses are left alone. Returns null if a invalid IP

console.log(storeIP('foo')); //null
console.log(storeIP('::ffff:')); //
console.log(storeIP('2001:0000:0111:0000:0011:0000:0001:0000')); //2001:0:111:0:11:0:1:0
console.log(storeIP('2001:0001:0000:0001:0000:0000:0000:0000')); //2001:1:0:1::
console.log(storeIP('0000:0000:0000:0000:0000:0000:0000:0000')); //::
console.log(storeIP('0000:0000:0000:0000:0000:0000:0000:0001')); //::1
console.log(storeIP('2041:0000:140F:0000:0000:0000:875B:131B')); //2041:0:140F::875B:131B
console.log(storeIP('2001:0001:0002:0003:0004:0005:0006:0007')); //2001:1:2:3:4:5:6:7
console.log(storeIP('')); //


Same function as storeIP, just a clearer name when you are using it for search instead


This function is useful for displaying IP addresses, such as after grabbing it back from the database when using storeIP

If an V6 addressed mapped as v4 is given it will convert it to V4, If any other V6 address is given it is normalized into the longer version and plain V4 addresses are left alone. Returns a empty string if a invalid IP

console.log(displayIP(null)); // ''
console.log(displayIP('::ffff:')); //''
console.log(displayIP('2001:0:111:0:11:0:1:0')); //'2001:0000:0111:0000:0011:0000:0001:0000'
console.log(displayIP('2001:1:0:1::')); //'2001:0001:0000:0001:0000:0000:0000:0000'
console.log(displayIP('::')); //'0000:0000:0000:0000:0000:0000:0000:0000'
console.log(displayIP('::1')); //'0000:0000:0000:0000:0000:0000:0000:0001'
console.log(displayIP('2041:0:140F::875B:131B')); //'2041:0000:140F:0000:0000:0000:875B:131B'
console.log(displayIP('2001:1:2:3:4:5:6:7')); //'2001:0001:0002:0003:0004:0005:0006:0007'
console.log(displayIP('')); //''


This project's Typescript conversion is powered by the TypeScript library starter which provides the following scripts.

  • yarn run test: Run test suite
  • yarn run start: Run npm run build in watch mode
  • yarn run test:watch: Run test suite in interactive watch mode
  • yarn run test:prod: Run linting and generate coverage
  • yarn run build: Generate bundles and typings, create docs
  • yarn run lint: Lints code
  • yarn run commit: Commit using conventional commit style (husky will tell you to use it if you haven't 😉)



Check if a IPv4 and/or IPv6 is within a range







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