nedb - npm Package Compare versions

Comparing version 1.7.1 to 1.7.2

lib/model.js

@@ -267,2 +267,5 @@ /**
  * Push an element to the end of an array field
+ * Optional modifier $each instead of value to push several values
+ * Optional modifier $slice to slice the resulting array, see https://docs.mongodb.org/manual/reference/operator/update/slice/
+ * Différeence with MongoDB: if $slice is specified and not $each, we act as if value is an empty array
  */
@@ -275,4 +278,8 @@ lastStepModifierFunctions.$push = function (obj, field, value) {
 
+  if (value !== null && typeof value === 'object' && value.$slice && value.$each === undefined) {
+    value.$each = [];
+  }
+
   if (value !== null && typeof value === 'object' && value.$each) {
-    if (Object.keys(value).length > 1) { throw new Error("Can't use another field in conjunction with $each"); }
+    if (Object.keys(value).length >= 3 || (Object.keys(value).length === 2 && value.$slice === undefined)) { throw new Error("Can only use $slice in cunjunction with $each when $push to array"); }
     if (!util.isArray(value.$each)) { throw new Error("$each requires an array value"); }
@@ -283,2 +290,18 @@
     });
+
+    if (value.$slice === undefined || typeof value.$slice !== 'number') { return; }
+
+    if (value.$slice === 0) {
+      obj[field] = [];
+    } else {
+      var start, end, n = obj[field].length;
+      if (value.$slice < 0) {
+        start = Math.max(0, n + value.$slice);
+        end = n;
+      } else if (value.$slice > 0) {
+        start = 0;
+        end = Math.min(n, value.$slice);
+      }
+      obj[field] = obj[field].slice(start, end);
+    }
   } else {
@@ -285,0 +308,0 @@ obj[field].push(value);

package.json

 {
   "name": "nedb",
-  "version": "1.7.1",
+  "version": "1.7.2",
   "author": {
@@ -5,0 +5,0 @@ "name": "Louis Chatriot",

README.md

@@ -418,3 +418,3 @@ <img src="http://i.imgur.com/9O1xHFb.png" style="width: 25%; height: 25%; float: left;">
   * A new document will replace the matched docs
-  * The modifiers create the fields they need to modify if they don't exist, and you can apply them to subdocs. Available field modifiers are `$set` to change a field's value, `$unset` to delete a field and `$inc` to increment a field's value. To work on arrays, you have `$push`, `$pop`, `$addToSet`, `$pull`, and the special `$each`. See examples below for the syntax.
+  * The modifiers create the fields they need to modify if they don't exist, and you can apply them to subdocs. Available field modifiers are `$set` to change a field's value, `$unset` to delete a field and `$inc` to increment a field's value. To work on arrays, you have `$push`, `$pop`, `$addToSet`, `$pull`, and the special `$each` and `$slice`. See examples below for the syntax.
 * `options` is an object with two possible parameters
@@ -514,9 +514,15 @@ * `multi` (defaults to `false`) which allows the modification of several documents if set to true
 
-
-
 // $each can be used to $push or $addToSet multiple values at once
 // This example works the same way with $addToSet
-db.update({ _id: 'id6' }, { $push: { fruits: {$each: ['banana', 'orange'] } } }, {}, function () {
+db.update({ _id: 'id6' }, { $push: { fruits: { $each: ['banana', 'orange'] } } }, {}, function () {
   // Now the fruits array is ['apple', 'orange', 'pear', 'banana', 'orange']
 });
+
+// $slice can be used in cunjunction with $push and $each to limit the size of the resulting array.
+// A value of 0 will update the array to an empty array. A positive value n will keep only the n first elements
+// A negative value -n will keep only the last n elements.
+// If $slice is specified but not $each, $each is set to []
+db.update({ _id: 'id6' }, { $push: { fruits: { $each: ['banana'], $slice: 2 } } }, {}, function () {
+  // Now the fruits array is ['apple', 'orange']
+});
 ```
@@ -523,0 +529,0 @@

test/model.test.js

@@ -211,3 +211,3 @@ var model = require('../lib/model')
     });
-    
+
     it('Can check if an object is a primitive or not', function () {
@@ -524,2 +524,43 @@ model.isPrimitiveType(5).should.equal(true);
 
+      it('Can use the $slice modifier to limit the number of array elements', function () {
+        var obj = { arr: ['hello'] }
+          , modified;
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: 1 } } });
+        assert.deepEqual(modified, { arr: ['hello'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: -1 } } });
+        assert.deepEqual(modified, { arr: ['everything'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: 0 } } });
+        assert.deepEqual(modified, { arr: [] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: 2 } } });
+        assert.deepEqual(modified, { arr: ['hello', 'world'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: -2 } } });
+        assert.deepEqual(modified, { arr: ['earth', 'everything'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: -20 } } });
+        assert.deepEqual(modified, { arr: ['hello', 'world', 'earth', 'everything'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: ['world', 'earth', 'everything'], $slice: 20 } } });
+        assert.deepEqual(modified, { arr: ['hello', 'world', 'earth', 'everything'] });
+
+        modified = model.modify(obj, { $push: { arr: { $each: [], $slice: 1 } } });
+        assert.deepEqual(modified, { arr: ['hello'] });
+
+        // $each not specified, but $slice is
+        modified = model.modify(obj, { $push: { arr: { $slice: 1 } } });
+        assert.deepEqual(modified, { arr: ['hello'] });
+
+        (function () {
+          modified = model.modify(obj, { $push: { arr: { $slice: 1, unauthorized: true } } });
+        }).should.throw();
+
+        (function () {
+          modified = model.modify(obj, { $push: { arr: { $each: [], unauthorized: true } } });
+        }).should.throw();
+      });
+
     });   // End of '$push modifier'
@@ -526,0 +567,0 @@

No alert changes

Improved metrics

Total package byte prevSize

1280875

increased by0.27%

Lines of code

28769

increased by0.17%

Number of lines in readme file

682

increased by0.89%

No dependency changes