rm old section on returns and logs

common-content/en/module/js1/errors/index.md

@@ -11,7 +11,6 @@ emoji= '❌'
   render = 'never'
   list = 'local'
   publishResources = false
-
 +++
 
 > 🗣️ Recall: A programming language is a set of rules for writing computer instructions.
@@ -28,16 +27,16 @@ const nationality = "Italian";
 
 On line 1, we have a variable declaration, but the string has a missing `"` We're not obeying the syntactic rules for JavaScript: the rules for writing expressions, statements and other parts of the language.
 
-When we execute the code above, we get this:
+When we execute the code above, we get a **SyntaxError**:
 
-```node
+```console
 const firstName = "Francesco;
                   ^^^^^^^^^^^
 
 Uncaught SyntaxError: Invalid or unexpected token
 ```
 
-We get a **SyntaxError** message. This error message is telling us that we've broken the rules of the language.
+This error message is telling us that we've broken the rules of the language.
 
 {{<note type="activity" title="Predict, Explain">}}
 
@@ -61,47 +60,3 @@ console.log(Math.round(10.3);
 ```
 
 {{</note>}}
-
-### Saving return values
-
-We can store the return value of a function in a variable. Function calls are also expressions. This means their value can also be stored in variables, just like with operations on numbers or strings.
-
-Suppose we have a file `arithmetic.js` containing this code:
-
-```js title="arithmetic.js"
-const result = Math.round(10.3);
-```
-
-When this program is executed, it creates a variable called `result` and assigns to it **the return value of the function**, in this case the rounded number.
-
-So `result` will have a value of `10`.
-
-### 🔭 Logging and returning
-
-Most functions return values we can use in our program.
-
-`Math.round` takes a single input, does a calculation and then returns a value that we can use when our program is running.
-
-Some functions don't produce useful return values in our running program; but they can still cause **effects**.
-
-{{<note title="Predict, Run, Observe" type="exercise">}}
-
-```js
-const result = console.log("hello world");
-```
-
-1. Predict what `result` will _evaluate to_ when the code above runs.
-1. Execute this line in the Node REPL.
-1. Evaluate the value of the `result` variable to observe what happens.
-
-{{</note>}}
-
-When this program runs, the variable `result` will evaluate to `undefined`. `undefined` is a data type in JavaScript which usually means no value has been assigned. Unlike the `number` data type, which contains many possible values (`1`, `2`, `10.3`, etc), the `undefined` data type has exactly one value, `undefined`.
-
-This can feel confusing as `console.log` _is_ a function with a set of instructions. `console.log` _does_ have an effect: it logs values to the console. However, `console.log` doesn't produce an output that we can use _inside_ the rest of our running program.
-
-{{<note type="tip">}}
-
-Key fact: `console.log` is used to print values to the terminal. It doesn’t produce an output in the running program.
-
-{{</note>}}