Complete the program

src/execWith.mjs

@@ -0,0 +1,10 @@
+export const execWith = execFunction => onError => command => {
+  try {
+    return execFunction(command, {
+      encoding: "utf8",
+      stdio: ["pipe", "pipe", "ignore"],
+    }).replace(/\n$/, "")
+  } catch (e) {
+    return onError(e)
+  }
+}

src/index.mjs

@@ -0,0 +1,41 @@
+import { execSync } from "child_process"
+import { execWith } from "./execWith.mjs"
+import { ExtendPipe } from "./Pipe.mjs"
+import { GetLatestVersion } from "./pipes/GetLatestVersion.mjs"
+import { MakeNewVersion } from "./pipes/MakeNewVersion.mjs"
+import { ExitIfNoVersion } from "./pipes/ExitIfNoVersion.mjs"
+import { GetVersionCommit } from "./pipes/GetVersionCommit.mjs"
+import { GetChanges } from "./pipes/GetChanges.mjs"
+import { ForceBump } from "./pipes/ForceBump.mjs"
+import { MakeChangelog } from "./pipes/MakeChangelog.mjs"
+import { Log } from "./pipes/Log.mjs"
+
+const argv = process.argv.slice(2)
+
+const conventions = {
+  patch: "^:bug: ",
+  minor: "^:sparkles: ",
+  major: "^:boom: ",
+}
+
+const execOrElse = execWith(execSync)
+const execOrExit = execOrElse(e => {
+  console.error(e.message || e)
+  process.exit(1)
+})
+
+const stdOut = str => process.stdout.write(str)
+
+const MakeChangelogIfRequired = argv.includes("--changelog")
+  ? MakeChangelog
+  : ExtendPipe.empty()
+
+GetLatestVersion(execOrElse(() => "0.0.0"))
+  .concat(GetVersionCommit(execOrExit))
+  .concat(GetChanges(execOrExit))
+  .concat(ForceBump)
+  .concat(MakeNewVersion)
+  .concat(ExitIfNoVersion(() => process.exit(0)))
+  .concat(MakeChangelogIfRequired)
+  .concat(Log(stdOut))
+  .run({ argv, conventions })

src/pipe.mjs

@@ -0,0 +1,15 @@
+const _fs = Symbol()
+
+const extend = f => obj => ({ ...obj, ...f(obj) })
+
+export const Pipe = (...fs) => ({
+  [_fs]: fs,
+  concat: o => Pipe(...fs.concat(o[_fs])),
+  run: initialContext => fs.reduce((acc, f) => f(acc), initialContext),
+})
+
+Pipe.empty = () => Pipe(x => x)
+
+export const ExtendPipe = (...fs) => Pipe(...fs.map(extend))
+
+ExtendPipe.empty = () => ExtendPipe(() => ({}))

src/pipes/ExitIfNoVersion.mjs

@@ -0,0 +1,6 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+export const ExitIfNoVersion = onNoNewVersion =>
+  ExtendPipe(({ newVersion, latestVersion }) =>
+    newVersion == latestVersion ? onNoNewVersion() : {},
+  )

src/pipes/ForceBump.mjs

@@ -0,0 +1,14 @@
+import { ExtendPipe } from "../Pipe.mjs"
+import { testConvention } from "../utils.mjs"
+
+export const ForceBump = ExtendPipe(
+  ({ changes, argv, conventions }) => ({
+    argv: Object.keys(conventions).reduce(
+      (acc, c) =>
+        changes.find(testConvention(conventions[c]))
+          ? acc.concat([`--${c}`])
+          : acc,
+      argv,
+    ),
+  }),
+)

src/pipes/GetChanges.mjs

@@ -0,0 +1,23 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+/**
+ * git-rev-list - Lists commit objects in reverse chronological order.
+ * @see https://git-scm.com/docs/git-rev-list
+ *
+ * * --oneline
+ * This is a shorthand for "--pretty=oneline --abbrev-commit".
+ *
+ * * --abbrev-commit
+ * Instead of showing the full 40-byte hexadecimal commit object name,
+ * show only a partial prefix.
+ *
+ * * --pretty=oneline
+ * Pretty-print the contents of the commit logs in one line.
+ */
+export const GetChanges = exec =>
+  ExtendPipe(({ latestVersionCommit }) => ({
+    changes: exec(`git rev-list ${latestVersionCommit}..HEAD --oneline`)
+      .split("\n")
+      .reverse()
+      .map(change => change.slice(change.indexOf(" ") + 1)),
+  }))

src/pipes/GetLatestVersion.mjs

@@ -0,0 +1,33 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+/**
+ * git-describe - Give an object a human readable name based on an
+ * available ref.
+ * @see https://git-scm.com/docs/git-describe
+ *
+ * * --tags
+ * Instead of using only the annotated tags, use any tag found in
+ * refs/tags namespace. This option enables matching a lightweight
+ * (non-annotated) tag.
+ *
+ * * --abbrev=<n>
+ * Instead of using the default 7 hexadecimal digits as the abbreviated
+ * object name, use <n> digits, or as many digits as needed to form a
+ * unique object name. An <n> of 0 will suppress long format, only
+ * showing the closest tag.
+ *
+ * * --match <pattern>
+ * Only consider tags matching the given glob(7) pattern, excluding the
+ * "refs/tags/" prefix.
+ *
+ * @warning The glob "*[0-9].*[0-9].*[0-9]" is not the perfect solution
+ * as it equally matches "1.0.0" and "1.foo0.bar0". It is used as a
+ * quick example here and real-life implementation should not rely on
+ * it.
+ */
+export const GetLatestVersion = exec =>
+  ExtendPipe(() => ({
+    latestVersion: exec(
+      `git describe --match "*[0-9].*[0-9].*[0-9]" --abbrev=0 HEAD --tags`,
+    ),
+  }))

src/pipes/GetVersionCommit.mjs

@@ -0,0 +1,32 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+/**
+ * git-rev-list - Lists commit objects in reverse chronological order.
+ * @see https://git-scm.com/docs/git-rev-list
+ *
+ * * --max-parents=0
+ * Show only commits which have at least (or at most) that many parent
+ * commits. In particular, --max-parents=0 gives all root commits.
+ *
+ * @warning If your repository contains multiple unrelated histories
+ * merged together, the `git rev-list --max-parents=0 HEAD` command
+ * will return you more than one commit.
+ *
+ * ====================================================================
+ *
+ * git-show-ref - List references in a local repository
+ * @see https://git-scm.com/docs/git-show-ref.
+ *
+ * * --hash
+ * Only show the SHA-1 hash, not the reference name.
+ */
+export const GetVersionCommit = (
+  execOnNoTags,
+  execOnTags = execOnNoTags,
+) =>
+  ExtendPipe(({ latestVersion }) => ({
+    latestVersionCommit:
+      latestVersion == "0.0.0"
+        ? execOnNoTags("git rev-list --max-parents=0 HEAD")
+        : execOnTags(`git show-ref ${latestVersion} -s`),
+  }))

src/pipes/Log.mjs

@@ -0,0 +1,6 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+export const Log = logger =>
+  ExtendPipe(({ newVersion, changelog }) =>
+    logger(changelog || newVersion),
+  )

src/pipes/MakeChangelog.mjs

@@ -0,0 +1,38 @@
+import { ExtendPipe } from "../Pipe.mjs"
+import { testConvention } from "../utils.mjs"
+
+const trimType = convention => change =>
+  change.replace(new RegExp(convention), "")
+
+const getMatchingChanges = (convention, changes) =>
+  changes.filter(testConvention(convention)).map(trimType(convention))
+
+const writeToChangelog = (title, items) =>
+  items.length
+    ? `\n## ${title}\n\n${items
+        .map(change => `* ${change}\n`)
+        .join("")}`
+    : ""
+
+const changelogTag = (_, version, breaks, features, fixes) =>
+  `# ${version}\n`
+    .concat(writeToChangelog("Breaking Changes", breaks))
+    .concat(writeToChangelog("Features & Deprecations", features))
+    .concat(writeToChangelog("Bug Fixes", fixes))
+
+export const MakeChangelog = ExtendPipe(
+  ({ changes, newVersion, conventions }) => ({
+    changelog: changelogTag`
+  # ${newVersion}
+
+  ## Breaking Changes
+  ${getMatchingChanges(conventions.major, changes)}
+
+  ## Features & Deprecations
+  ${getMatchingChanges(conventions.minor, changes)}
+
+  ## Bug Fixes
+  ${getMatchingChanges(conventions.patch, changes)}
+`,
+  }),
+)

src/pipes/MakeNewVersion.mjs

@@ -0,0 +1,21 @@
+import { ExtendPipe } from "../Pipe.mjs"
+
+const splitVersionToNumbers = ({ latestVersion }) => ({
+  newVersion: latestVersion.split(".").map(Number),
+})
+
+const joinVersionNumbers = ({ newVersion }) => ({
+  newVersion: newVersion.join("."),
+})
+
+const bump = (option, bumpFunc) => ({ newVersion, argv }) => ({
+  newVersion: argv.includes(option) ? bumpFunc(newVersion) : newVersion,
+})
+
+export const MakeNewVersion = ExtendPipe(
+  splitVersionToNumbers,
+  bump("--patch", tuple => [tuple[0], tuple[1], tuple[2] + 1]),
+  bump("--minor", tuple => [tuple[0], tuple[1] + 1, 0]),
+  bump("--major", tuple => [tuple[0] + 1, 0, 0]),
+  joinVersionNumbers,
+)

src/utils.mjs

@@ -0,0 +1,2 @@
+export const testConvention = convention => change =>
+  new RegExp(convention).test(change)

tests/0_2_Pipe.spec.mjs

@@ -1,4 +1,4 @@
-import { ExtendPipe, Pipe } from "../src/pipe.mjs"
+import { ExtendPipe, Pipe } from "../src/Pipe.mjs"
 import { describe, expect, it } from "./clown.mjs"
 
 describe("Pipe", () => {

tests/index.mjs

@@ -1,11 +1,11 @@
 import "./clown.spec.mjs"
-// import "./0_1_execWith.spec.mjs"
-// import "./0_2_Pipe.spec.mjs"
-// import "./1_GetLatestVersion.spec.mjs"
-// import "./2_MakeNewVersion.spec.mjs"
-// import "./3_ExitIfNoVersion.spec.mjs"
-// import "./4_GetVersionCommit.spec.mjs"
-// import "./5_GetChanges.spec.mjs"
-// import "./6_ForceBump.spec.mjs"
-// import "./7_MakeChangelog.spec.mjs"
-// import "./8_Log.spec.mjs"
+import "./0_1_execWith.spec.mjs"
+import "./0_2_Pipe.spec.mjs"
+import "./1_GetLatestVersion.spec.mjs"
+import "./2_MakeNewVersion.spec.mjs"
+import "./3_ExitIfNoVersion.spec.mjs"
+import "./4_GetVersionCommit.spec.mjs"
+import "./5_GetChanges.spec.mjs"
+import "./6_ForceBump.spec.mjs"
+import "./7_MakeChangelog.spec.mjs"
+import "./8_Log.spec.mjs"