Add option to separate named imports

This addresses #116

Add a `-separate-named` boolean option.  When activated, named/aliased
imports are split off into a separate block below the relevant group,
e.g. named std below std, named project below project, etc.

README.md

@@ -84,6 +84,8 @@ Usage of goimports-reviser:
     	Apply rules recursively if target is a directory. In case of ./... execution will be recursively applied by default. Optional parameter.
   -rm-unused
     	Remove unused imports. Optional parameter.
+  -separate-named
+        Separate named imports from their group with a new line. Optional parameter.
   -set-alias
     	Set alias for versioned package names, like 'github.com/go-pg/pg/v9'. In this case import will be set as 'pg "github.com/go-pg/pg/v9"'. Optional parameter.
   -set-exit-status
@@ -238,6 +240,36 @@ func additionalTest(){
 }
 ```
 
+### Example with `-separate-named`-option
+
+Before usage:
+
+```go
+package testdata // goimports-reviser/testdata
+
+import (
+	"fmt"
+	"github.com/incu6us/goimports-reviser/pkg"
+	extpkg "google.com/golang/pkg"
+	"golang.org/x/exp/slices"
+	extslice "github.com/PeterRK/slices"
+)
+```
+
+After usage:
+```go
+package testdata // goimports-reviser/testdata
+
+import (
+	"fmt"
+
+	"github.com/incu6us/goimports-reviser/pkg"
+	"golang.org/x/exp/slices"
+
+	extpkg "google.com/golang/pkg"
+	extslice "github.com/PeterRK/slices"
+)
+```
 ---
 
 ## Give a Star! ⭐

main.go

@@ -31,6 +31,7 @@ const (
 	useCacheArg            = "use-cache"
 	applyToGeneratedFiles  = "apply-to-generated-files"
 	excludesArg            = "excludes"
+	separateNamedArg       = "separate-named"
 
 	// Deprecated options
 	localArg    = "local"
@@ -49,6 +50,7 @@ var (
 	shouldSetAlias              *bool
 	shouldFormat                *bool
 	shouldApplyToGeneratedFiles *bool
+	shouldSeparateNamedImports  *bool
 	listFileName                *bool
 	setExitStatus               *bool
 	isRecursive                 *bool
@@ -150,6 +152,12 @@ Optional parameter.`,
 		"Option will perform additional formatting. Optional parameter.",
 	)
 
+	shouldSeparateNamedImports = flag.Bool(
+		separateNamedArg,
+		false,
+		"Option will separate named imports from the rest of the imports, per group. Optional parameter.",
+	)
+
 	isRecursive = flag.Bool(
 		recursiveArg,
 		false,
@@ -238,6 +246,10 @@ func main() {
 		options = append(options, reviser.WithSkipGeneratedFile)
 	}
 
+	if shouldSeparateNamedImports != nil && *shouldSeparateNamedImports {
+		options = append(options, reviser.WithSeparatedNamedImports)
+	}
+
 	if localPkgPrefixes != "" {
 		if companyPkgPrefixes != "" {
 			companyPkgPrefixes = localPkgPrefixes

reviser/file.go

@@ -35,6 +35,7 @@ type SourceFile struct {
 	shouldUseAliasForVersionSuffix bool
 	shouldFormatCode               bool
 	shouldSkipAutoGenerated        bool
+	shouldSeparateNamedImports     bool
 	hasSeparateSideEffectGroup     bool
 	companyPackagePrefixes         []string
 	importsOrders                  ImportsOrders
@@ -165,12 +166,16 @@ func (f *SourceFile) groupImports(
 	importsWithMetadata map[string]*commentsMetadata,
 ) *groupsImports {
 	var (
-		stdImports       []string
-		projectImports   []string
-		projectLocalPkgs []string
-		generalImports   []string
-		blankedImports   []string
-		dottedImports    []string
+		stdImports            []string
+		projectImports        []string
+		projectLocalPkgs      []string
+		generalImports        []string
+		namedStdImports       []string
+		namedProjectImports   []string
+		namedProjectLocalPkgs []string
+		namedGeneralImports   []string
+		blankedImports        []string
+		dottedImports         []string
 	)
 
 	for imprt := range importsWithMetadata {
@@ -185,14 +190,33 @@ func (f *SourceFile) groupImports(
 		}
 
 		pkgWithoutAlias := skipPackageAlias(imprt)
+		values := strings.Split(imprt, " ")
+
 		if _, ok := std.StdPackages[pkgWithoutAlias]; ok {
+			if f.shouldSeparateNamedImports {
+				if len(values) > 1 {
+					namedStdImports = append(namedStdImports, imprt)
+				} else {
+					stdImports = append(stdImports, imprt)
+				}
+				continue
+			}
 			stdImports = append(stdImports, imprt)
 			continue
 		}
 
 		var isLocalPackageFound bool
 		for _, localPackagePrefix := range localPkgPrefixes {
 			if strings.HasPrefix(pkgWithoutAlias, localPackagePrefix) && !strings.HasPrefix(pkgWithoutAlias, projectName) {
+				if f.shouldSeparateNamedImports {
+					if len(values) > 1 {
+						namedProjectLocalPkgs = append(namedProjectLocalPkgs, imprt)
+					} else {
+						projectLocalPkgs = append(projectLocalPkgs, imprt)
+					}
+					isLocalPackageFound = true
+					break
+				}
 				projectLocalPkgs = append(projectLocalPkgs, imprt)
 				isLocalPackageFound = true
 				break
@@ -204,10 +228,26 @@ func (f *SourceFile) groupImports(
 		}
 
 		if strings.Contains(pkgWithoutAlias, projectName) {
+			if f.shouldSeparateNamedImports {
+				if len(values) > 1 {
+					namedProjectImports = append(namedProjectImports, imprt)
+				} else {
+					projectImports = append(projectImports, imprt)
+				}
+				continue
+			}
 			projectImports = append(projectImports, imprt)
 			continue
 		}
 
+		if f.shouldSeparateNamedImports {
+			if len(values) > 1 {
+				namedGeneralImports = append(namedGeneralImports, imprt)
+			} else {
+				generalImports = append(generalImports, imprt)
+			}
+			continue
+		}
 		generalImports = append(generalImports, imprt)
 	}
 
@@ -217,13 +257,21 @@ func (f *SourceFile) groupImports(
 	sort.Strings(projectImports)
 	sort.Strings(blankedImports)
 	sort.Strings(dottedImports)
+	sort.Strings(namedStdImports)
+	sort.Strings(namedGeneralImports)
+	sort.Strings(namedProjectLocalPkgs)
+	sort.Strings(namedProjectImports)
 
 	result := &groupsImports{
 		common: &common{
-			std:     stdImports,
-			general: generalImports,
-			company: projectLocalPkgs,
-			project: projectImports,
+			std:          stdImports,
+			namedStd:     namedStdImports,
+			general:      generalImports,
+			namedGeneral: namedGeneralImports,
+			company:      projectLocalPkgs,
+			namedCompany: namedProjectLocalPkgs,
+			project:      projectImports,
+			namedProject: namedProjectImports,
 		},
 		blanked: blankedImports,
 		dotted:  dottedImports,

reviser/file_option.go

@@ -53,3 +53,8 @@ func WithSkipGeneratedFile(f *SourceFile) error {
 	f.shouldSkipAutoGenerated = true
 	return nil
 }
+
+func WithSeparatedNamedImports(f *SourceFile) error {
+	f.shouldSeparateNamedImports = true
+	return nil
+}

reviser/file_test.go

@@ -1999,3 +1999,139 @@ import (
 		})
 	}
 }
+
+func TestSourceFile_Fix_WithSeparatedNamedImports(t *testing.T) {
+	type args struct {
+		projectName string
+		filePath    string
+		fileContent string
+	}
+	tests := []struct {
+		name       string
+		args       args
+		want       string
+		wantChange bool
+		wantErr    bool
+	}{
+		{
+			name: "simple",
+			args: args{
+				projectName: "github.com/incu6us/goimports-reviser",
+				filePath:    "./testdata/example.go",
+				fileContent: `package testdata
+import (
+	"fmt"
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+	"bytes"
+	"golang.org/x/exp/slices"
+)
+`,
+			},
+			want: `package testdata
+
+import (
+	"bytes"
+	"fmt"
+
+	"golang.org/x/exp/slices"
+
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+)
+`,
+			wantChange: true,
+			wantErr:    false,
+		},
+		{
+			name: "named",
+			args: args{
+				projectName: "github.com/incu6us/goimports-reviser",
+				filePath:    "./testdata/example.go",
+				fileContent: `package testdata
+import (
+	"fmt"
+	second "github.com/incu6us/goimports-reviser/testdata/secondpkg"
+	by "bytes"
+	js "encoding/json"
+	"golang.org/x/exp/slices"
+	er "golang.org/x/errors"
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+)
+`,
+			},
+			want: `package testdata
+
+import (
+	"fmt"
+
+	by "bytes"
+	js "encoding/json"
+
+	"golang.org/x/exp/slices"
+
+	er "golang.org/x/errors"
+
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+
+	second "github.com/incu6us/goimports-reviser/testdata/secondpkg"
+)
+`,
+			wantChange: true,
+			wantErr:    false,
+		},
+		{
+			name: "named with comments",
+			args: args{
+				projectName: "github.com/incu6us/goimports-reviser",
+				filePath:    "./testdata/example.go",
+				fileContent: `package testdata
+import (
+	"fmt" //fmt package
+	second "github.com/incu6us/goimports-reviser/testdata/secondpkg" //secondpkg package
+	by "bytes"
+	js "encoding/json"
+	"golang.org/x/exp/slices" //slices package
+	er "golang.org/x/errors"
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+)
+`,
+			},
+			want: `package testdata
+
+import (
+	"fmt" //fmt package
+
+	by "bytes"
+	js "encoding/json"
+
+	"golang.org/x/exp/slices" //slices package
+
+	er "golang.org/x/errors"
+
+	"github.com/incu6us/goimports-reviser/testdata/innderpkg"
+
+	second "github.com/incu6us/goimports-reviser/testdata/secondpkg" //secondpkg package
+)
+`,
+			wantChange: true,
+			wantErr:    false,
+		},
+	}
+
+	for _, tt := range tests {
+		if tt.args.filePath != StandardInput && !strings.Contains(tt.args.filePath, "does-not-exist") {
+			require.NoError(t, os.WriteFile(tt.args.filePath, []byte(tt.args.fileContent), 0o644))
+		}
+
+		t.Run(tt.name, func(t *testing.T) {
+			got, _, hasChange, err := NewSourceFile(tt.args.projectName, tt.args.filePath).Fix(WithSeparatedNamedImports)
+			if tt.wantErr {
+				assert.Error(t, err)
+				return
+			}
+
+			assert.NoError(t, err)
+			assert.Equal(t, tt.wantChange, hasChange)
+			assert.Equal(t, tt.want, string(got))
+		})
+	}
+}