feat(publish/index.js): Added OutputJson Command

Outputs the packages and versions from publishing to a JSON file.

commands/publish/README.md

@@ -65,6 +65,7 @@ This is useful when a previous `lerna publish` failed to publish all packages to
 - [`--tag-version-prefix`](#--tag-version-prefix)
 - [`--temp-tag`](#--temp-tag)
 - [`--yes`](#--yes)
+- [`--summary-file <dir/filename>`](#--summary-file)
 
 ### `--canary`
 
@@ -291,6 +292,27 @@ lerna publish --canary --yes
 When run with this flag, `lerna publish` will skip all confirmation prompts.
 Useful in [Continuous integration (CI)](https://en.wikipedia.org/wiki/Continuous_integration) to automatically answer the publish confirmation prompt.
 
+### `--summary-file`
+
+```sh
+lerna publish --canary --yes --summary-file ./output.json
+```
+
+When run with this flag, once a successfully publish it will create a json summary report(see below for an example).
+
+```json
+[
+  {
+    "packageName": "package1",
+    "version": "v1.0.1-alpha"
+  },
+  {
+    "packageName": "package2",
+    "version": "v2.0.1-alpha"
+  }
+]
+```
+
 ## Deprecated Options
 
 ### `--skip-npm`

commands/publish/__tests__/publish-command.test.js

@@ -34,6 +34,8 @@ const initFixture = require("@lerna-test/init-fixture")(__dirname);
 const path = require("path");
 const fs = require("fs-extra");
 
+const fsmain = require("fs");
+
 // file under test
 const lernaPublish = require("@lerna-test/command-runner")(require("../command"));
 
@@ -306,6 +308,31 @@ Map {
     });
   });
 
+  describe("--summary-file", () => {
+    it("skips creating the summary file", async () => {
+      const cwd = await initFixture("normal");
+      const fsSpy = jest.spyOn(fs, "writeFileSync");
+      await lernaPublish(cwd);
+
+      expect(fsSpy).not.toHaveBeenCalled();
+    });
+
+    it("creates the summary file", async () => {
+      const cwd = await initFixture("normal");
+      const fsSpy = jest.spyOn(fsmain, "writeFileSync");
+      await lernaPublish(cwd)("--summary-file", "./output.json");
+
+      const expectedJsonResponse = [
+        { packageName: "package-1", version: "1.0.1" },
+        { packageName: "package-2", version: "1.0.1" },
+        { packageName: "package-3", version: "1.0.1" },
+        { packageName: "package-4", version: "1.0.1" },
+      ];
+      expect(fsSpy).toHaveBeenCalled();
+      expect(fsSpy).toHaveBeenCalledWith("./output.json", JSON.stringify(expectedJsonResponse));
+    });
+  });
+
   describe("--no-verify-access", () => {
     it("skips package access verification", async () => {
       const cwd = await initFixture("normal");

commands/publish/command.js

@@ -110,6 +110,11 @@ exports.builder = (yargs) => {
       hidden: true,
       type: "boolean",
     },
+    "summary-file": {
+      // Json output.
+      hidden: true,
+      type: "string",
+    },
     // y: {
     //   describe: "Skip all confirmation prompts.",
     //   alias: "yes",