Merge pull request #1625 from strongloop/fix-list-of-class-instances

Allow List to take items as instances of a class

lib/list.js

@@ -63,9 +63,13 @@ function List(items, itemType, parent) {
     });
   }
 
+  List.prototype.toItem = function(item) {
+    return isClass(this.itemType) ? new this.itemType(item) : this.itemType(item);
+  };
+
   items.forEach(function(item, i) {
     if (itemType && !(item instanceof itemType)) {
-      arr[i] = itemType(item);
+      arr[i] = arr.toItem(item);
     } else {
       arr[i] = item;
     }
@@ -79,7 +83,7 @@ util.inherits(List, Array);
 var _push = List.prototype.push;
 
 List.prototype.push = function(obj) {
-  var item = this.itemType && (obj instanceof this.itemType) ? obj : this.itemType(obj);
+  var item = this.itemType && (obj instanceof this.itemType) ? obj : this.toItem(obj);
   _push.call(this, item);
   return item;
 };
@@ -117,3 +121,6 @@ List.prototype.toString = function() {
   return JSON.stringify(this.toJSON());
 };
 
+function isClass(fn) {
+  return fn && fn.toString().indexOf('class ') === 0;
+}

test/kv-memory.js

@@ -1,3 +1,8 @@
+// Copyright IBM Corp. 2013,2016. All Rights Reserved.
+// Node module: loopback-datasource-juggler
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
 'use strict';
 var kvMemory = require('../lib/connectors/kv-memory');
 var DataSource = require('..').DataSource;

test/kvao.suite.js

@@ -1,3 +1,8 @@
+// Copyright IBM Corp. 2013,2016. All Rights Reserved.
+// Node module: loopback-datasource-juggler
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
 'use strict';
 
 var debug = require('debug')('test');

test/list.test.js

@@ -0,0 +1,124 @@
+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: loopback-datasource-juggler
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+'use strict';
+
+var should = require('./init.js');
+var List = require('../lib/list');
+
+/**
+ * Phone as a class
+ */
+class Phone {
+  constructor(label, num) {
+    this.label = label;
+    this.num = num;
+  }
+
+  toJSON() {
+    return {
+      label: this.label,
+      num: this.num,
+    };
+  }
+}
+
+/**
+ * Phone as a constructor function
+ * @param {string} label
+ * @param {number} num
+ */
+function PhoneCtor(label, num) {
+  if (!(this instanceof PhoneCtor)) {
+    return new PhoneCtor(label, num);
+  }
+  this.label = label;
+  this.num = num;
+}
+
+describe('list of items typed by a class', function() {
+  it('allows itemType to be a class', function() {
+    var phones = givenPhones();
+
+    var list = new List(phones, Phone);
+    list.should.be.an.instanceOf(Array);
+    list.toJSON().should.be.eql(phones);
+  });
+
+  it('converts items of plain json to the itemType', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List(phones, Phone);
+    list[0].should.be.an.instanceOf(Phone);
+  });
+
+  it('converts stringified items to the itemType', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List(JSON.stringify(phones), Phone);
+    list[0].should.be.an.instanceOf(Phone);
+  });
+
+  it('converts items of plain json to the itemType with push', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List([], Phone);
+    list.push(phones[0]);
+    list[0].should.be.an.instanceOf(Phone);
+  });
+});
+
+describe('list of items typed by a ctor', function() {
+  it('allows itemType to be a ctor', function() {
+    var phones = givenPhonesWithCtor();
+
+    var list = new List(phones, PhoneCtor);
+    list.should.be.an.instanceOf(Array);
+    list.toJSON().should.be.eql(phones);
+  });
+
+  it('converts items of plain json to the itemType', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List(phones, PhoneCtor);
+    list[0].should.be.an.instanceOf(PhoneCtor);
+  });
+
+  it('converts stringified items to the itemType', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List(JSON.stringify(phones), PhoneCtor);
+    list[0].should.be.an.instanceOf(PhoneCtor);
+  });
+
+  it('converts items of plain json to the itemType with push', function() {
+    var phones = givenPhonesAsJSON();
+
+    var list = new List([], PhoneCtor);
+    list.push(phones[0]);
+    list[0].should.be.an.instanceOf(PhoneCtor);
+  });
+});
+
+function givenPhones() {
+  return [
+    new Phone('home', '111-222-3333'),
+    new Phone('work', '111-222-5555'),
+  ];
+}
+
+function givenPhonesWithCtor() {
+  return [
+    new PhoneCtor('home', '111-222-3333'),
+    PhoneCtor('work', '111-222-5555'),
+  ];
+}
+
+function givenPhonesAsJSON() {
+  return [
+    {label: 'home', num: '111-222-3333'},
+    {label: 'work', num: '111-222-5555'},
+  ];
+}