JavaScript / ECMAScript

npm Package Name in JS

Validate npm package names including scoped packages (@org/package), per the npm naming spec.

Try it in the JS tester →

Pattern

regexJS
^(?:@[a-z0-9\-*~][a-z0-9\-*._~]*\/)?[a-z0-9\-~][a-z0-9\-._~]*$

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("^(?:@[a-z0-9\\-*~][a-z0-9\\-*._~]*\\/)?[a-z0-9\\-~][a-z0-9\\-._~]*$", "");
const input = "react";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

How the pattern works

The optional group (?:@[a-z0-9\-*~][a-z0-9\-*._~]*\/)? matches a @scope/ prefix for scoped packages. The main name [a-z0-9\-~][a-z0-9\-._~]* matches lowercase letters, digits, hyphens, dots, and tildes. Uppercase is not allowed per npm rules.

Examples

Input

react

Matches

  • react

Input

@types/node

Matches

  • @types/node

Input

MyPackage

No match

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Same pattern, other engines

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

Go (RE2)

Supported

See how this pattern looks (and behaves) in Go's `regexp` package (RE2 engine).

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