[WIP] Extract code to validate a version bump

Author: romaricpascal

packages/releases/bin/update-changelog.js

@@ -1,23 +1,20 @@
 #!/usr/bin/env node
 
 const { resolve } = require('node:path')
-const { writeFileSync } = require('node:fs')
+const { writeFileSync, readFileSync } = require('node:fs')
 
-const semver = require('semver')
-
-const { readFileLinesSync, versionIsAPrerelease, getPrereleaseIdentifier, getChangelogLineIndexes } = require('../changelog-release-helper.js')
+const { getChangelogLineIndexes } = require('../changelog-release-helper.js')
 
 const config = require('../config.js')
+const { VersionBump } = require('../version-bump.js')
 
 if (require.main === module) {
   // npm exposes these environment variable as part of the lifecycle hooks
   // (https://github.com/npm/cli/blob/c97b39b1e3436cd20a67ab5f4012a5f395c538b9/workspaces/libnpmversion/lib/version.js#L100-L103)
   const { npm_old_version: previousVersion, npm_new_version: newVersion } =
     process.env
 
-  if (!previousVersion || !newVersion) {
-    throw new Error('Both previous and new version must be set to continue.')
-  }
+  const bump = new VersionBump(newVersion, previousVersion)
 
   console.log(
     `Updating changelog from version ${previousVersion} to ${newVersion}...`
@@ -26,7 +23,7 @@ if (require.main === module) {
   // Use `resolve` to find the CHANGELOG.md file relative to the current working directory
   const changelogPath = resolve(process.argv[2] ?? 'CHANGELOG.md')
 
-  updateChangelog(changelogPath, newVersion, previousVersion)
+  updateChangelog(changelogPath, bump)
 }
 
 /**
@@ -36,118 +33,60 @@ if (require.main === module) {
  * content
  *
  * @param {string} path - Path to the CHANGELOG file
- * @param {string} newVersion - New version to add to the changelog
- * @param {string} previousVersion - Previous version. Used for calculating difference
- *   in versions to build the changelog title
+ * @param {VersionBump} bump - New version to add to the changelog
  */
-function updateChangelog (path, newVersion, previousVersion) {
-  const validatedNewVersion = validateVersionNumber(newVersion)
-  const validatedPreviousVersion = validateVersionNumber(previousVersion)
-
-  // Skip the entire function if the release version is internal eg: 5.1.0-internal.0
-  const newVersionIsAPrerelease = versionIsAPrerelease(validatedNewVersion)
-  if (newVersionIsAPrerelease) {
-    const identifier = getPrereleaseIdentifier(validatedNewVersion)
-
-    if (identifier === 'internal') {
-      console.log(
-        'This is an internal release, intended for testing only. The changelog will therefore not be updated.'
-      )
-      return
-    }
-  }
-
-  const changelogLines = readFileLinesSync(path)
-  const [startIndex] = getChangelogLineIndexes(changelogLines)
+function updateChangelog (path, bump) {
 
-  const versionDiff = semver.diff(validatedNewVersion, validatedPreviousVersion)
-  if (!versionDiff) {
-    throw new Error(`New version (${validatedNewVersion}) and previous version (${validatedPreviousVersion}) are the same`)
-  }
-  const newVersionTitle = `## ${validatedNewVersion} (${capitalise(convertIncTypeWord(versionDiff, validatedNewVersion))})`
-
-  const newLines = [newVersionTitle, '']
-  if (newVersionIsAPrerelease) {
-    newLines.push(
-      config.prereleaseWarning(removePrereleaseFlag(validatedNewVersion)),
-      ''
-    )
-    // Add content for installing pre-releases
-    newLines.push(
-      config.prereleaseInstallationInstructions(validatedNewVersion),
-      ''
-    )
-  } else {
-    // Add content on how to install the release
-    newLines.push(
-      config.installationInstructions(),
-      ''
-    )
+  if (!bump.needsChangelogUpdate) {
+    console.log('This is an internal release, intended for testing only. The changelog will therefore not be updated.')
+    return
   }
 
-  // Inject the new lines into the CHANGELOG
-  changelogLines.splice(startIndex + 1, 0, '', ...newLines)
+  updateFile(path, (content) => {
+    const changelogLines = content.split('\n');
 
-  writeFileSync(path, changelogLines.join('\n'))
-}
-
-/**
- * Validates the version number that it is a semantic versioned string.
- *
- * @param {string} version - version number
- * @returns {string} - Validated semver of version
- */
-function validateVersionNumber (version) {
-  const validatedVersion = semver.valid(version)
+    const [startIndex] = getChangelogLineIndexes(changelogLines)
 
-  if (!validatedVersion) {
-    throw new Error(
-      `Version number "${version}" could not be parsed as a semantic versioned string.`
-    )
-  }
+    const newVersionTitle = `## ${bump.newVersion} (${capitalise(bump.releaseLabel)})`
 
-  return validatedVersion
-}
-
-/**
- * Convert a standard SemVer increment word eg: major, minor or patch into the
- * wording we use for release titles.
- *
- * @param {string} incType - SemVer increment type
- * @param {string|null} version - SemVer version
- * @returns {string} - The reworded increment type
- */
-function convertIncTypeWord (incType, version) {
-  let rewordedIncType = incType
-
-  // If there's a prerelease flag e.g. 1.0.0-beta.0 use that to decide
-  const prereleaseIdentifier = getPrereleaseIdentifier(version)
-  if (prereleaseIdentifier) {
-    if (prereleaseIdentifier === 'rc') {
-      return 'release candidate'
+    const newLines = [newVersionTitle, '']
+    if (bump.toPrerelease) {
+      newLines.push(
+        config.prereleaseWarning(bump.withoutPrereleaseTag),
+        ''
+      )
+      // Add content for installing pre-releases
+      newLines.push(
+        config.prereleaseInstallationInstructions(bump.newVersion),
+        ''
+      )
+    } else {
+      // Add content on how to install the release
+      newLines.push(
+        config.installationInstructions(),
+        ''
+      )
     }
-    rewordedIncType = prereleaseIdentifier
-  } else if (incType === 'major') {
-    rewordedIncType = 'breaking'
-  } else if (incType === 'minor') {
-    rewordedIncType = 'feature'
-  } else if (incType === 'patch') {
-    rewordedIncType = 'fix'
-  }
 
-  return `${rewordedIncType} release`
+    // Inject the new lines into the CHANGELOG
+    changelogLines.splice(startIndex + 1, 0, '', ...newLines)
+
+    return changelogLines.join('\n');
+  })
 }
 
 /**
- * Remove any pre-release flag from a version e.g. 1.0.0-alpha -> 1.0.0
- *
- * @param {string} version - version number
- * @returns {string} - version number without any pre-release flag
+ * Updates file at given path with the result from the given function
+ * 
+ * @param {string} path - The path of the file to update
+ * @param {string => string | null | undefined} callback - The function updating the content 
  */
-function removePrereleaseFlag (version) {
-  const parsedVersion = semver.parse(version)
-  parsedVersion.prerelease = []
-  return parsedVersion.format()
+function updateFile(path, callback) {
+  const content = readFileSync(path, {encoding: 'utf-8'});
+  const updatedContent = callback(content);
+  if (updatedContent) {
+    writeFileSync(path, content)
+  }
 }
 
 /**

packages/releases/version-bump.js

@@ -0,0 +1,77 @@
+const semver = require('semver')
+
+const {versionIsAPrerelease, getPrereleaseIdentifier } = require('./changelog-release-helper.js');
+
+class VersionBump {
+  constructor(newVersion, previousVersion) {
+
+    if (!previousVersion || !newVersion) {
+      throw new Error('Both previous and new version must be set to continue.')
+    }
+    
+    this.newVersion = validateVersionNumber(newVersion)
+    this.previousVersion = validateVersionNumber(previousVersion)
+    this.toPrerelease = versionIsAPrerelease(this.newVersion);
+    
+    if (this.toPrerelease) {
+      const identifier = getPrereleaseIdentifier(this.newVersion)
+
+      this.needsChangelogUpdate = identifier === 'internal'
+    }
+
+    this.versionDiff = semver.diff(this.newVersion, this.previousVersion)
+
+    if (!this.versionDiff) {
+      throw new Error(`New version (${this.newVersion}) and previous version (${this.previousVersion}) are the same`)
+    }
+  }
+
+  get releaseLabel() {
+    let rewordedIncType = this.versionDiff
+
+    // If there's a prerelease flag e.g. 1.0.0-beta.0 use that to decide
+    const prereleaseIdentifier = getPrereleaseIdentifier(this.newVersion)
+    if (prereleaseIdentifier) {
+      if (prereleaseIdentifier === 'rc') {
+        return 'release candidate'
+      }
+      rewordedIncType = prereleaseIdentifier
+    } else if (incType === 'major') {
+      rewordedIncType = 'breaking'
+    } else if (incType === 'minor') {
+      rewordedIncType = 'feature'
+    } else if (incType === 'patch') {
+      rewordedIncType = 'fix'
+    }
+
+    return `${rewordedIncType} release`
+  }
+
+  get withoutPrereleaseTag() {  
+    const parsedVersion = semver.parse(this.newVersion)
+    parsedVersion.prerelease = []
+    return parsedVersion.format()
+  }
+}
+
+/**
+ * Validates the version number that it is a semantic versioned string.
+ *
+ * @param {string} version - version number
+ * @returns {string} - Validated semver of version
+ */
+function validateVersionNumber (version) {
+  const validatedVersion = semver.valid(version)
+
+  if (!validatedVersion) {
+    throw new Error(
+      `Version number "${version}" could not be parsed as a semantic versioned string.`
+    )
+  }
+
+  return validatedVersion
+}
+
+module.exports = {
+    VersionBump
+}