feat: redirect console output

[OutOfBedlam]

Add ability to re-direct console.log() to io.Writer instead of os.Stdout.

example

var buf = &bytes.Buffer{}
vm := otto.New(otto.WithStdoutWriter(buf))
vm.Run(`console.log('hello', 'world');`)

fmt.Println(buf.String())

[stevenh]

Nice addition thanks for the PR.

I've put some suggestions of how we could improve it a little.

[stevenh]

suggestion: lets set the default so we can simplify the use after.

Suggested change

	for _, opt := range opts {
	o.runtime.console = os.Stdout
	for _, opt := range opts {

[stevenh]

suggestion: with the use of a default we can simply this.

Suggested change

	var w io.Writer
	if call.runtime.stdoutWriter != nil {
	w = call.runtime.stdoutWriter
	} else {
	w = os.Stdout
	}
	fmt.Fprintln(w, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
	fmt.Fprintln(call.runtime.console, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.

[stevenh]

suggestion: simplify as above.

Suggested change

	var w io.Writer
	if call.runtime.stdoutWriter != nil {
	w = call.runtime.stdoutWriter
	} else {
	w = os.Stdout
	}
	fmt.Fprintln(w, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
	fmt.Fprintln(call.runtime.console, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.

[stevenh]

suggestion: lets document the type.

[stevenh]

suggestion: lets document the type and change the naming so it easier for the user to understand the impact of using this option.

Suggested change

	func WithStdoutWriter(w io.Writer) Option {
	return func(o *Otto) {
	o.runtime.stdoutWriter = w
	// WithConsoleOutput sets the target for console output.
	// Default: Stdout.
	func WithConsoleOutput(w io.Writer) Option {
	return func(o *Otto) {
	o.runtime.console = w

[stevenh]

suggestion: can we use sub tests vs table driven as its more concise and allows developers to run specific tests directly from their editor e.g. VS Code.

Also the use of just a declared buffer vs instantiated is more idiomatic.

Not tested the below, so there might be typos, but you get the idea 😃

Suggested change

	func TestOtterStdoutWriter(t *testing.T) {
	tests := []struct {
	name string
	script string
	expect string
	}{
	{
	name: "console.log",
	script: "console.log('hello', 'world')",
	expect: "hello world\n",
	},
	{
	name: "console.err",
	script: "console.error('error', 'world')",
	expect: "error world\n",
	},
	}
	for _, tc := range tests {
	t.Run(tc.name, func(t *testing.T) {
	var buf = &bytes.Buffer{}
	vm := New(WithStdoutWriter(buf))
	_, err := vm.Run(tc.script)
	require.NoError(t, err)
	require.Equal(t, tc.expect, buf.String())
	})
	}
	}
	func TestOtto_WithConsoleOutput(t *testing.T) {
	t.Run('console.log', func(t *testing.T) {
	var buf bytes.Buffer
	vm := New(WithConsoleOutput(&buf))
	_, err := vm.Run("console.log('hello', 'world')")
	require.NoError(t, err)
	require.Equal(t, "hello world\n", buf.String())
	})
	t.Run('console.err', func(t *testing.T) {
	var buf bytes.Buffer
	vm := New(WithConsoleOutput(&buf))
	_, err := vm.Run("console.error('world')")
	require.NoError(t, err)
	require.Equal(t, "error world\n", buf.String())
	})
	}

[stevenh]

suggestion: make it clear the use vs the value

Suggested change

	stdoutWriter io.Writer
	console io.Writer