Problem when attach on "aldeed:collection2-core"

I tried aldeed:collection2-core, simpl-schema2, but have problem on Posts.attachSchema(Posts.schema)

import {Mongo} from 'meteor/mongo';
import SimpleSchema2 from 'simpl-schema';
// import { SimpleSchema } from 'meteor/aldeed:simple-schema';

const Posts = new Mongo.Collection('posts');

Posts.schema = new SimpleSchema2({
  createdDate: {
    type: Date,
  },
  title: {
    type: String,
  },
  body: {
    type: String,
  },
});

Posts.attachSchema(Posts.schema);
export default Posts;

It show

 Error: Invalid definition for pick field.
W20170329-10:07:49.304(7)? (STDERR)     at packages/aldeed_simple-schema.js:1429:13
W20170329-10:07:49.304(7)? (STDERR)     at Function._.each._.forEach (packages/underscore.js:147:22)
W20170329-10:07:49.304(7)? (STDERR)     at [object Object].SimpleSchema (packages/aldeed_simple-schema.js:1426:5)
W20170329-10:07:49.304(7)? (STDERR)     at [object Object].c2AttachSchema [as attachSchema] (packages/aldeed_collection2-core.js:62:10)
W20170329-10:07:49.305(7)? (STDERR)     at meteorInstall.imports.api.posts.posts.js (imports/api/posts/posts.js:27:16)
W20170329-10:07:49.305(7)? (STDERR)     at fileEvaluate (packages/modules-runtime.js:197:9)
W20170329-10:07:49.305(7)? (STDERR)     at Module.require (packages/modules-runtime.js:120:16)
W20170329-10:07:49.305(7)? (STDERR)     at Module.Mp.importSync (/Users/theara/.meteor/packages/modules/.0.9.0-beta.13.ag5gz5++os+web.browser+web.cordova/npm/node_modules/reify/lib/runtime.js:88:16)
W20170329-10:07:49.306(7)? (STDERR)     at meteorInstall.imports.api.posts.methods.js (imports/api/posts/methods.js:1:1)
W20170329-10:07:49.306(7)? (STDERR)     at fileEvaluate (packages/modules-runtime.js:197:9)

And then I tried to remove Posts.attachSchema(Posts.schema);, It work fine.

[tamacti]

Right now it’s possible to use another approach as described here: { friends: { type: Array }, 'friends.$': { type: String }, } Actually, there mentioned that we can use { friends: [String], } but it doesn’t work.

[SevenZark]

My problem turned out to be that, for some reason, when I added an unspecified version of collection2-core, I wound up with an older version. Per the advice of somebody in a different thread, I uninstalled all the old aldeed stuff, then did this:

meteor add aldeed:collection2-core@2.0.1

This fixed my problem.