Improve test names and prevent some solutions

exercises/concept/recycling-robot/.docs/hints.md

@@ -40,14 +40,14 @@
 - `typeof` returns a string.
 - You can check the length of an array to find out how many elements it contains.
 
-## 8. Throw an error if an object does not have the `id` property or method
+## 8. Check if an object has a `type` property or method
 
 - You can use the `in` operator to check if an object has a property or method.
-- If the `id` property or method is missing, your function should throw an `Error`.
 
-## 9. Check if an object has a `type` property or method
+## 9. Throw an error if an object does not have the `id` property or method
 
 - You can use the `in` operator to check if an object has a property or method.
+- If the `id` property or method is missing, your function should throw an `Error`.
 
 ## 10. Check if an object has an `id` property
 

exercises/concept/recycling-robot/.docs/instructions.md

@@ -52,7 +52,8 @@ isObject(25n);
 
 ### 4. Check if a string is numeric
 
-Implement the `isNumericString` function, that should check if the value is a string that only consists of digits.
+Implement the `isNumericString` function, that should check if the value is a string that only consists of digits or a minus followed by digits indicating a negative number.
+Only integers should be considered, decimals are not considered numeric for this check of the recycling robot.
 
 ```javascript
 isNumericString(42);
@@ -109,21 +110,7 @@ isEmptyArray([]);
 // => true
 ```
 
-### 8. Throw an error if an object does not have an `id` property or method
-
-Implement the `assertHasId` function, that will throw an `Error` if an object is missing the `id` property.
-
-If an object does have the `id` property, it should not return anything.
-
-```javascript
-assertHasId({ id: 42, color: 'red' });
-// => undefined
-
-assertHasId({ color: 'green' });
-// Error: "Object is missing the 'id' property"
-```
-
-### 9. Check if an object has a `type` property or method
+### 8. Check if an object has a `type` property or method
 
 Implement the `hasType` function, that checks whether an object has a `type` property or method.
 
@@ -133,40 +120,62 @@ class Keyboard(){
     // ...
   }
 }
-hasType({type:"car",color:"red"})
+hasType({ type:"car", color:"red" })
 // => true
 
-hasType({color:"green"})
+hasType({ color:"green" })
 // => false
 
 hasType(new Keyboard())
 // => true
 ```
 
+### 9. Throw an error if an object does not have an `id` property or method
+
+Implement the `assertHasId` function, that will throw an `Error` if an object is missing the `id` property.
+
+If an object does have the `id` property, it should not return anything.
+
+```javascript
+assertHasId({ id: 42, color: 'red' });
+// => undefined
+
+assertHasId({ color: 'green' });
+// Error: "Object is missing the 'id' property"
+```
+
 ### 10. Check if an object has an `id` property
 
 Implement the `hasIdProperty` function, that checks whether an object has an `id` property.
 
 ```javascript
-class MyClass {
+class SimpleData {
   constructor() {
     this.number = '42';
     this.id = 'BC269327FE1D9B95';
   }
 }
-class MyNewClass {
+
+class StealingData extends SimpleData {}
+
+class MethodData {
   constructor() {
     this.number = '42';
     this._id = 'BC269327FE1D9B95';
   }
+
   get id() {
     return this._id;
   }
 }
-hasIdProperty(new MyClass());
+
+hasIdProperty(new SimpleData());
 // => true
 
-hasIdProperty(new MyNewClass());
+hasIdProperty(new MethodData());
+// => false
+
+hasIdProperty(new StealingData());
 // => false
 ```
 

exercises/concept/recycling-robot/.meta/exemplar.js

@@ -24,9 +24,7 @@ export function isBoolean(value) {
  */
 export function isNumber(value) {
   return (
-    (typeof value === 'number' || typeof value === 'bigint') &&
-    !isNaN(Number(value)) &&
-    value !== Infinity
+    (typeof value === 'number' && isFinite(value)) || typeof value === 'bigint'
   );
 }
 
@@ -47,12 +45,7 @@ export function isObject(value) {
  * @returns {boolean} whether the input is a numeric string.
  */
 export function isNumericString(value) {
-  return (
-    typeof value === 'string' &&
-    value.split('').every((char) => {
-      return /[0-9]/.test(char);
-    })
-  );
+  return typeof value === 'string' && /^-?\d+$/.test(value);
 }
 
 /**
@@ -86,26 +79,27 @@ export function isEmptyArray(value) {
 }
 
 /**
- * Throws an error if an object is missing an "id" property or method.
+ * Checks if a value has a "type" property or method.
  *
  * @param {object} object
- * @returns {boolean} undefined if the input has an "id" property, otherwise throws an error.
+ * @returns {boolean} whether the input has a "type" property.
  */
-export function assertHasId(object) {
-  if ('id' in object) {
-    return;
-  }
-  throw new Error('The "id" property is missing.');
+export function hasType(object) {
+  return 'type' in object;
 }
 
 /**
- * Checks if a value has a "type" property or method.
+ * Throws an error if an object is missing an "id" property or method.
  *
  * @param {object} object
- * @returns {boolean} whether the input has a "type" property.
+ * @returns {never|void} undefined if the input has an "id" property, otherwise throws an error.
  */
-export function hasType(object) {
-  return 'type' in object;
+export function assertHasId(object) {
+  if ('id' in object) {
+    return;
+  }
+
+  throw new Error('The "id" property is missing.');
 }
 
 /**

exercises/concept/recycling-robot/assembly-line.js

@@ -81,23 +81,23 @@ export function isEmptyArray(value) {
 }
 
 /**
- * Throws an error if an object is missing an "id" property or method.
+ * Checks if a value has a "type" property or method.
  *
  * @param {object} object
- * @returns {undefined} undefined if the input has an "id" property or method, otherwise throws an error.
+ * @returns {boolean} whether the input has a "type" property or method.
  */
-export function assertHasId(object) {
-  throw new Error('Remove this line and implement the assertHasId function');
+export function hasType(object) {
+  throw new Error('Remove this line and implement the hasType function');
 }
 
 /**
- * Checks if a value has a "type" property or method.
+ * Throws an error if an object is missing an "id" property or method.
  *
  * @param {object} object
- * @returns {boolean} whether the input has a "type" property or method.
+ * @returns {never|void} undefined if the input has an "id" property or method, otherwise throws an error.
  */
-export function hasType(object) {
-  throw new Error('Remove this line and implement the hasType function');
+export function assertHasId(object) {
+  throw new Error('Remove this line and implement the assertHasId function');
 }
 
 /**