Git copy contents

git.ts

import { $ } from 'dax-sh'

export const getCommitHashFromTagName = async (
  tagName: string,
  cwd: string
): Promise<string | null> => {
  try {
    const v = await $`git rev-list -n 1 ${tagName}`.cwd(cwd).quiet()
    return v.stdout.trim()
  } catch {
    return null
  }
}

export const isValidCommitHash = async (hash: string, cwd: string): Promise<boolean> => {
  try {
    // taken from https://stackoverflow.com/a/31780867
    const type = '^{commit}' // done to escape this, otherwise the cmd fails
    await $`git cat-file -e ${hash}${type}`.cwd(cwd).quiet()
    return true
  } catch (err) {
    return false
  }
}

interface CopyGitRepoContentsArgs {
  gitRepoRoot: string
  commitHash: string
  pathToCopy: string
  toDir: string
}

export const copyGitRepoContents = async ({
  commitHash,
  gitRepoRoot,
  pathToCopy,
  toDir,
}: CopyGitRepoContentsArgs): Promise<void> => {
  // devised from https://stackoverflow.com/questions/4479960/checkout-to-a-specific-folder and docs
  await $`git worktree add -d --no-checkout ${toDir}`.cwd(gitRepoRoot).quiet()
  await $`git checkout ${commitHash} -- ${pathToCopy}`.cwd(toDir).quiet()
}

export const postCopyGitRepoContents = async ({
  gitRepoRoot,
  toDir,
}: Pick<CopyGitRepoContentsArgs, 'toDir' | 'gitRepoRoot'>): Promise<void> => {
  await $`rm -r .git`.cwd(toDir) // makes the dir prunable
  await $`git worktree prune`.cwd(gitRepoRoot) // only removes the dangling entries, doesn't deletes their folder
}

usage.ts

async function copyConfigFiles(
  projectRoot: string,
  commitHash: string,
  configDirRelativeToProjectRoot: string,
  toDir: string
) {
  try {
    await copyGitRepoContents({
      gitRepoRoot: projectRoot,
      commitHash,
      pathToCopy: configDirRelativeToProjectRoot,
      toDir: toDir,
    })
    await postCopyGitRepoContents({
      gitRepoRoot: projectRoot,
      toDir: toDir,
    })
  } catch {
    await postCopyGitRepoContents({
      gitRepoRoot: projectRoot,
      toDir: toDir,
    })
    return Promise.reject(
      `Couldn't make a copy of config files. Does ${configDirRelativeToProjectRoot} exists in ${commitHash} commit hash?`
    )
  }
}