Add function to get version from package.json (#10)

* Add function to get version from package.json package_json_parser needs to parse version to be re-used in npm-install buildpack. Signed-off-by: Michael Dawson <[email protected]> * squash: add cleanup of workingDir Signed-off-by: Michael Dawson <[email protected]> --------- Signed-off-by: Michael Dawson <[email protected]>
paketo-buildpacks · Jun 29, 2023 · 8bac97c · 8bac97c
1 parent 4b5928b
commit 8bac97c
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diff --git a/package_json.go b/package_json.go
@@ -9,6 +9,9 @@ import (
 
 // PackageJSON represents the contents of a package.json file.
 type PackageJSON struct {
+	Engines struct {
+		Node string `json:"node"`
+	} `json:"engines"`
 	Scripts struct {
 		PostStart string `json:"poststart"`
 		PreStart  string `json:"prestart"`
@@ -38,3 +41,7 @@ func ParsePackageJSON(path string) (PackageJSON, error) {
 func (pj PackageJSON) HasStartScript() bool {
 	return pj.Scripts.Start != ""
 }
+
+func (pj PackageJSON) GetVersion() string {
+	return pj.Engines.Node
+}
diff --git a/package_json_test.go b/package_json_test.go
@@ -34,6 +34,10 @@ func testPackageJSON(t *testing.T, context spec.G, it spec.S) {
 		}`), 0600)).To(Succeed())
 	})
 
+	it.After(func() {
+		Expect(os.RemoveAll(workingDir)).To(Succeed())
+	})
+
 	context("when parsing a valid package.json with start scripts", func() {
 		it("successfully extracts the scripts information", func() {
 			pkg, err := libnodejs.ParsePackageJSON(path)
@@ -88,4 +92,50 @@ func testPackageJSON(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 	})
+
+	context("ParseVersion", func() {
+		it.Before(func() {
+			Expect(os.WriteFile(filePath, []byte(`{
+				"engines": {
+					"node": "1.2.3"
+				}
+			}`), 0600)).To(Succeed())
+		})
+
+		it("parses the node engine version from a package.json file", func() {
+			pkg, err := libnodejs.ParsePackageJSON(workingDir)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(pkg.GetVersion()).To(Equal("1.2.3"))
+		})
+
+		context("Engines, but no Node version", func() {
+			it.Before(func() {
+				Expect(os.WriteFile(filePath, []byte(`{
+					"engines": {
+					}
+				}`), 0600)).To(Succeed())
+			})
+
+			it("parses the node engine version from a package.json file when no version is specified", func() {
+
+				pkg, err := libnodejs.ParsePackageJSON(workingDir)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(pkg.GetVersion()).To(Equal(""))
+			})
+		})
+
+		context("No Engines", func() {
+			it.Before(func() {
+				Expect(os.WriteFile(filePath, []byte(`{
+				}`), 0600)).To(Succeed())
+			})
+
+			it("parses the node engine version from a package.json file when no version is specified", func() {
+
+				pkg, err := libnodejs.ParsePackageJSON(workingDir)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(pkg.GetVersion()).To(Equal(""))
+			})
+		})
+	})
 }