fix: package-lock.json custom indentation

package-lock.json files should follow the same indentation used on
package.json files.

This commit fixes the issue by forwarding the proper indent selected for
package.json to Shrinkwarp.save method. Also, added tests asserting
appropriate tab-indentation for both files.

Fixes: npm/cli#1662

PR-URL: #141
Credit: @ruyadorno
Close: #141
Reviewed-by: @isaacs

lib/arborist/reify.js

@@ -822,7 +822,10 @@ module.exports = cls => class Reifier extends cls {
     const json = (JSON.stringify(pjData, null, format) + '\n')
       .replace(/\n/g, eol)
 
-    const saveOpt = { format: this[_formatPackageLock] }
+    const saveOpt = {
+      format: (this[_formatPackageLock] && format) ? format
+      : this[_formatPackageLock],
+    }
     return Promise.all([
       this[_usePackageLock] && this.idealTree.meta.save(saveOpt),
       writeFile(pj, json),

lib/shrinkwrap.js

@@ -912,7 +912,9 @@ class Shrinkwrap {
       throw new Error('run load() before saving data')
 
     const { format = true } = options
-    const indent = format ? this.indent || 2 : 0
+    const defaultIndent = this.indent || 2
+    const indent = format === true ? defaultIndent
+      : format || 0
     const eol = format ? this.newline || '\n' : ''
     const data = this.commit()
     const json = stringify(data, swKeyOrder, indent).replace(/\n/g, eol)

tap-snapshots/test-arborist-reify.js-TAP.test.js

@@ -27084,6 +27084,48 @@ Object {
 }
 `
 
+exports[`test/arborist/reify.js TAP store files with a custom indenting > must match snapshot 1`] = `
+{
+	"name": "tab-indented-package-json",
+	"version": "1.0.0",
+	"dependencies": {
+		"abbrev": "^1.0.0"
+	}
+}
+
+`
+
+exports[`test/arborist/reify.js TAP store files with a custom indenting > must match snapshot 2`] = `
+{
+	"name": "tab-indented-package-json",
+	"version": "1.0.0",
+	"lockfileVersion": 2,
+	"requires": true,
+	"packages": {
+		"": {
+			"name": "tab-indented-package-json",
+			"version": "1.0.0",
+			"dependencies": {
+				"abbrev": "^1.0.0"
+			}
+		},
+		"node_modules/abbrev": {
+			"version": "1.1.1",
+			"resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.1.tgz",
+			"integrity": "sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q=="
+		}
+	},
+	"dependencies": {
+		"abbrev": {
+			"version": "1.1.1",
+			"resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.1.tgz",
+			"integrity": "sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q=="
+		}
+	}
+}
+
+`
+
 exports[`test/arborist/reify.js TAP tarball deps with transitive tarball deps > expect resolving Promise 1`] = `
 Node {
   "children": Map {

tap-snapshots/test-shrinkwrap.js-TAP.test.js

@@ -14276,6 +14276,16 @@ Object {
 }
 `
 
+exports[`test/shrinkwrap.js TAP saving dependency-free shrinkwrap object load file, and save it with a custom format > custom indented json output 1`] = `
+{
+	"lockfileVersion": 2,
+	"requires": true,
+	"packages": {},
+	"dependencies": {}
+}
+
+`
+
 exports[`test/shrinkwrap.js TAP saving dependency-free shrinkwrap object load the unindented file, and save it back default > indented json output 1`] = `
 {
   "lockfileVersion": 2,

test/arborist/reify.js

@@ -1002,6 +1002,20 @@ t.test('add a dep present in the tree, with v1 shrinkwrap', async t => {
   t.matchSnapshot(fs.readFileSync(path + '/package.json', 'utf8'))
 })
 
+t.test('store files with a custom indenting', async t => {
+  const tabIndentedPackageJson =
+    fs.readFileSync(
+      resolve(__dirname, '../fixtures/tab-indented-package-json/package.json'),
+      'utf8'
+    )
+  const path = t.testdir({
+    'package.json': tabIndentedPackageJson
+  })
+  const tree = await reify(path)
+  t.matchSnapshot(fs.readFileSync(path + '/package.json', 'utf8'))
+  t.matchSnapshot(fs.readFileSync(path + '/package-lock.json', 'utf8'))
+})
+
 t.test('modules bundled by the root should be installed', async t => {
   const path = fixture(t, 'root-bundler')
   const tree = await reify(path)

test/fixtures/tab-indented-package-json/package.json

@@ -0,0 +1,7 @@
+{
+	"name": "tab-indented-package-json",
+	"version": "1.0.0",
+	"dependencies": {
+		"abbrev": "^1.0.0"
+	}
+}

test/shrinkwrap.js

@@ -438,6 +438,17 @@ t.test('saving dependency-free shrinkwrap object', t => {
     t.matchSnapshot(fs.readFileSync(sw.filename, 'utf8'), 'indented json output')
   })
 
+  t.test('load file, and save it with a custom format', async t => {
+    const sw = await Shrinkwrap.load({ path: dir })
+    t.equal(
+      sw.filename,
+      resolve(`${dir}/package-lock.json`),
+      'correct filepath on shrinkwrap instance'
+    )
+    await sw.save({ format: '\t' })
+    t.matchSnapshot(fs.readFileSync(sw.filename, 'utf8'), 'custom indented json output')
+  })
+
   t.end()
 })