Go's path.Match in TypeScript

✓ Verified: Go 1.23

How to use

Install via yarn add locutus and import: import { Match } from 'locutus/golang/path/Match'.

Or with CommonJS: const { Match } = require('locutus/golang/path/Match')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	`Match('*.go', 'main.go')`	`true`
2	`Match('a/?/c', 'a/b/c')`	`true`
3	`Match('a/*.go', 'a/b/main.go')`	`false`
4	`Match('[a-c]at', 'bat')`	`true`

Notes

Supports Go-style wildcards *, ?, and character classes [].
Returns false for malformed patterns.

Here's what our current TypeScript equivalent to Go's path.Match looks like.

const escapeRegexChar = (char: string): string => {
  return /[\\^$.*+?()[\]{}|]/.test(char) ? `\\${char}` : char
}

const toPathRegex = (pattern: string): RegExp | null => {
  let regex = '^'
  let index = 0

  while (index < pattern.length) {
    const char = pattern[index] ?? ''

    if (char === '*') {
      regex += '[^/]*'
      index += 1
      continue
    }

    if (char === '?') {
      regex += '[^/]'
      index += 1
      continue
    }

    if (char === '[') {
      let cursor = index + 1
      let negate = false

      const firstClassChar = pattern[cursor]
      if (firstClassChar === '!' || firstClassChar === '^') {
        negate = true
        cursor += 1
      }

      if (cursor >= pattern.length) {
        return null
      }

      let content = ''
      let sawAny = false
      for (; cursor < pattern.length; cursor += 1) {
        const classChar = pattern[cursor] ?? ''
        if (classChar === ']' && sawAny) {
          break
        }
        sawAny = true

        if (classChar === '\\') {
          const escaped = pattern[cursor + 1]
          if (escaped === undefined) {
            return null
          }
          content += escapeRegexChar(escaped)
          cursor += 1
          continue
        }

        if (classChar === ']') {
          content += '\\]'
        } else {
          content += classChar
        }
      }

      if (cursor >= pattern.length || pattern[cursor] !== ']') {
        return null
      }

      regex += `[${negate ? '^' : ''}${content}]`
      index = cursor + 1
      continue
    }

    if (char === '\\') {
      const escaped = pattern[index + 1]
      if (escaped === undefined) {
        return null
      }
      regex += escapeRegexChar(escaped)
      index += 2
      continue
    }

    regex += char === '/' ? '/' : escapeRegexChar(char)
    index += 1
  }

  regex += '$'
  return new RegExp(regex)
}

export function Match(pattern: string, name: string): boolean {
  //      discuss at: https://locutus.io/golang/path/Match
  // parity verified: Go 1.23
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Supports Go-style wildcards *, ?, and character classes [].
  //          note 2: Returns false for malformed patterns.
  //       example 1: Match('*.go', 'main.go')
  //       returns 1: true
  //       example 2: Match('a/?/c', 'a/b/c')
  //       returns 2: true
  //       example 3: Match('a/*.go', 'a/b/main.go')
  //       returns 3: false
  //       example 4: Match('[a-c]at', 'bat')
  //       returns 4: true

  const expression = toPathRegex(String(pattern))
  if (!expression) {
    return false
  }

  return expression.test(String(name))
}

Improve this function

Locutus is a community effort following The McDonald's Theory: we ship first iterations, hoping others will improve them. If you see something that could be better, we'd love your contribution.

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Help us add more

Got a rainy Sunday afternoon and a taste for a porting puzzle?

Get inspiration from Go strings documentation, Go strings source, Go strings examples source, GopherJS.
Click "New file" in the appropriate folder on GitHub. This will fork the project to your account, directly add the file to it, and send a Pull Request to us.

We will then review it. If it's useful to the project and in line with our contributing guidelines your work will become part of Locutus and you'll be automatically credited in the authors section accordingly.

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