Fix yarn list --json stdOut parsing. fixes #388

lib/packagers/yarn.js

@@ -62,7 +62,13 @@ class Yarn {
         return BbPromise.reject(err);
       })
       .then(processOutput => processOutput.stdout)
-      .then(depJson => BbPromise.try(() => JSON.parse(depJson)))
+      .then(stdout =>
+        BbPromise.try(() => {
+          const lines = Utils.splitLines(stdout);
+          const parsedLines = _.map(lines, Utils.safeJsonParse);
+          return _.find(parsedLines, line => line && line.type === 'tree');
+        })
+      )
       .then(parsedTree => {
         const convertTrees = trees =>
           _.reduce(

lib/packagers/yarn.test.js

@@ -61,14 +61,22 @@ describe('yarn', () => {
     });
 
     it('should transform yarn trees to npm dependencies', () => {
-      const testYarnResult = `{"type":"tree","data":{"type":"list","trees":[
-        {"name":"[email protected]","children":[],"hint":null,"color":"bold",
-        "depth":0},{"name":"[email protected]","children":[],"hint":null,"color":
-        "bold","depth":0},{"name":"[email protected]","children":[],"hint":null,
-        "color":"bold","depth":0},{"name":"[email protected]","children":[{"name":
-        "[email protected]","children":[],"hint":null,"color":"bold","depth":0}],
-        "hint":null,"color":null,"depth":0},{"name":"@sls/[email protected]", 
-        "children":[],"hint":null,"color":"bold","depth":0}]}}`;
+      const testYarnResult =
+        '{"type":"activityStart","data":{"id":0}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"archiver@^2.1.1"}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"bluebird@^3.5.1"}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"fs-extra@^4.0.3"}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"mkdirp@^0.5.1"}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"minimist@^0.0.8"}}\n' +
+        '{"type":"activityTick","data":{"id":0,"name":"@sls/webpack@^1.0.0"}}\n' +
+        '{"type":"tree","data":{"type":"list","trees":[' +
+        '{"name":"[email protected]","children":[],"hint":null,"color":"bold",' +
+        '"depth":0},{"name":"[email protected]","children":[],"hint":null,"color":' +
+        '"bold","depth":0},{"name":"[email protected]","children":[],"hint":null,' +
+        '"color":"bold","depth":0},{"name":"[email protected]","children":[{"name":' +
+        '"[email protected]","children":[],"hint":null,"color":"bold","depth":0}],' +
+        '"hint":null,"color":null,"depth":0},{"name":"@sls/[email protected]",' +
+        '"children":[],"hint":null,"color":"bold","depth":0}]}}\n';
       const expectedResult = {
         problems: [],
         dependencies: {

lib/utils.js

@@ -96,10 +96,24 @@ function spawnProcess(command, args, options) {
   });
 }
 
+function safeJsonParse(str) {
+  try {
+    return JSON.parse(str);
+  } catch (e) {
+    return null;
+  }
+}
+
+function splitLines(str) {
+  return _.split(str, /\r?\n/);
+}
+
 module.exports = {
   guid,
   purgeCache,
   searchAndProcessCache,
   SpawnError,
-  spawnProcess
+  spawnProcess,
+  safeJsonParse,
+  splitLines
 };

lib/utils.test.js

@@ -118,4 +118,20 @@ describe('Utils', () => {
       return expect(Utils.spawnProcess('cmd', [])).to.be.rejectedWith(Utils.SpawnError);
     });
   });
+
+  describe('safeJsonParse', () => {
+    it('should parse valid JSON', () => {
+      expect(Utils.safeJsonParse('{"foo": "bar"}')).to.deep.equal({ foo: 'bar' });
+    });
+
+    it('should return null for invalid JSON', () => {
+      expect(Utils.safeJsonParse('{"foo":')).to.equal(null);
+    });
+  });
+
+  describe('splitLines', () => {
+    it('should split on new line characters', () => {
+      expect(Utils.splitLines('a\r\nb\nc')).to.deep.equal([ 'a', 'b', 'c' ]);
+    });
+  });
 });