fix: Respect package.json indentation (#77)

Respects the user's indentation in their `package.json`

Fixes #68

package.json

@@ -26,6 +26,7 @@
  "chalk": "^1.1.3",
  "cli-cursor": "^2.1.0",
  "cli-spinners": "^1.0.0",
+ "detect-indent": "^5.0.0",
  "es6-error": "^4.0.2",
  "pify": "^3.0.0",
  "semver": "^5.3.0",

src/tasks/updatePackageJson.js

@@ -1,3 +1,4 @@
+import detectIndent from "detect-indent";
 import createUpdatedPackageJson from "./util/createUpdatedPackageJson";
 import Sequence from "./util/Sequence";
 
@@ -6,7 +7,8 @@ function lastChar(str) {
 }
 
 function stringify(newPackageJson, oldPackageJsonStr) {
- let newPackageJsonStr = JSON.stringify(newPackageJson, null, " ");
+ const indent = detectIndent(oldPackageJsonStr).indent || " ";
+ let newPackageJsonStr = JSON.stringify(newPackageJson, null, indent);
  const lastCharFromOldPackageJson = lastChar(oldPackageJsonStr);
 
  // Preserve the new line character at the end if there was one

test/tasks/updatePackageJson.test.js

@@ -66,6 +66,25 @@ describe("updatePackageJson()", () => {
  )
  );
  });
+ it("should respect indentation", async () => {
+ const updtr = new FakeUpdtr();
+ const updateResults = [];
+ const fourSpacedPackageJson = outdatedRegular.replace(/ {2}/g, " ");
+ const tabbedPackageJson = outdatedRegular.replace(/ {2}/g, "\t");
+
+ updtr.writeFile.resolves();
+
+ updtr.readFile.resolves(fourSpacedPackageJson);
+
+ await updatePackageJson(updtr, updateResults);
+
+ updtr.readFile.resolves(tabbedPackageJson);
+
+ await updatePackageJson(updtr, updateResults);
+
+ expect(updtr.writeFile.getCall(0).args[1]).toBe(fourSpacedPackageJson);
+ expect(updtr.writeFile.getCall(1).args[1]).toBe(tabbedPackageJson);
+ });
  it("should emit the expected events", async () => {
  const updtr = new FakeUpdtr();
  const updateResults = [module1ToLatestSuccess];