Throw exception for unregistered operators

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 3.0.1 / 2020-04-xx
+
+- Throw exception for specifying unregistered operators
+
 ## 3.0.0 / 2020-04-12
 
 - Convert project to Typescript

Makefile

@@ -9,4 +9,6 @@ clean:
 	@npm run clean
 
 test:
-	@npm run test
+	@npm run test
+
+.PHONY: test

README.md

@@ -119,14 +119,14 @@ The following two examples are equivalent.
 
 ```js
 import { $unwind } from 'mingo/operators/pipeline'
-
 ```
 
 #### ES5
 
-```js
-const $unwind = require('mingo/operators/pipeline').$unwind
+Unlike the ES6 version, it is necessary to specify the operator module in the path to avoid loading any extras
 
+```js
+const $unwind = require('mingo/operators/pipeline/unwind').$unwind
 ```
 
 ## Configuration

src/core.ts

@@ -216,25 +216,30 @@ export function computeValue(obj: object | any[], expr: any, operator: string, o
   options = options || { config: null }
   options.config = options.config || createConfig()
 
-  // if the field of the object is a valid operator
-  let call = getOperator(OperatorType.EXPRESSION, operator)
-  if (call) return call(obj, expr, options)
-
-  // we also handle $group accumulator operators
-  call = getOperator(OperatorType.ACCUMULATOR, operator)
-  if (call) {
-
-    // if object is not an array, first try to compute using the expression
-    if (!isArray(obj)) {
-      obj = computeValue(obj, expr, null, options)
-      expr = null
-    }
+  if (isOperator(operator)) {
+    // if the field of the object is a valid operator
+    let call = getOperator(OperatorType.EXPRESSION, operator)
+    if (call) return call(obj, expr, options)
+
+    // we also handle $group accumulator operators
+    call = getOperator(OperatorType.ACCUMULATOR, operator)
+    if (call) {
+
+      // if object is not an array, first try to compute using the expression
+      if (!isArray(obj)) {
+        obj = computeValue(obj, expr, null, options)
+        expr = null
+      }
 
-    // validate that we have an array
-    assert(isArray(obj), `${operator} target must be an array.`)
+      // validate that we have an array
+      assert(isArray(obj), `'${operator}' target must be an array.`)
+
+      // we pass a null expression because all values have been resolved
+      return call(obj, expr, options)
+    }
 
-    // we pass a null expression because all values have been resolved
-    return call(obj, expr, options)
+    // operator was not found
+    throw new Error(`operator '${operator}' is not registered`)
   }
 
   // if expr is a variable for an object field

src/operators/pipeline/group.ts

@@ -18,7 +18,7 @@ export function $group(collection: Iterator, expr: any, options: Options): Itera
   let id = expr[ID_KEY]
 
   return collection.transform(coll => {
-    let partitions = groupBy(coll, obj => computeValue(obj, id, id, options))
+    let partitions = groupBy(coll, obj => computeValue(obj, id, null, options))
 
     // remove the group key
     expr = into({}, expr)