Another common occurrence during iterative development within a REPL

environment is forgetting variable names or failing to remember what

variables have already been declared.

Thankfully, you can run

```javascript

vars()

```

to return a list of user-defined variable names. For additional variable

details, run

```javascript

help( vars )

```

to see function options.

To facilitate working with long variable names and nested property access,

the REPL supports \*TAB\s completion.

For example, enter

```javascript

base.rand

```

followed by \*TAB\s to generate a list of auto-completions.

Similarly, if you create a nested object

```javascript

var obj = { 'beep': { 'boop': { 'foo': 'bar' } } };

```

and then enter

```javascript

obj.beep.b

```

followed by \*TAB\s, the nested property \*boop\s should auto-complete.

\*TAB\s completion also works with computed properties. For example, enter

```javascript

obj[ 'beep' ][ 'b

```

followed by \*TAB\s to auto-complete the nested property \*boop\s as done

in the previous slide.

---

For select APIs interacting with the filesystem, \*TAB\s completion is

supported for file paths.

For example, enter

```javascript

readFile.sync( './

```

followed by \*TAB\s to generate a list of applicable file paths.

---

Additionally, \*TAB\s completion is supported for variables defined in a

nested scope.

For example, enter

```javascript

function foo() { var beep = 5; be

```

followed by \*TAB\s to auto-complete the variable \*beep\s.

Similarly, entering

```javascript

function foo( beep ) { console.log( be

```

followed by \*TAB\s auto-completes the parameter \*beep\s.