A single file diff checker in your terminal.
I put this together some time ago and use it frequently, thought others here might use it to.
Just do:
Code
go mod init diffterm
create main.go
go mod tidyThen build it with:
Code
go build -o difftermHere's the code for main.go:
Code
package main
import (
"strings"
"time"
"github.com/gdamore/tcell/v2"
"github.com/rivo/tview"
"github.com/sergi/go-diff/diffmatchpatch"
"fmt"
)
func countLines(s string) int {
if s == "" {
return 0
}
return len(strings.Split(s, "\n"))
}
// Returns the count of lines added and removed (inserted/deleted lines only)
func diffLineCounts(orig, updated string) (added, removed int) {
dmp := diffmatchpatch.New()
diffs := dmp.DiffMain(orig, updated, false)
for _, d := range diffs {
switch d.Type {
case diffmatchpatch.DiffInsert:
added += countLines(d.Text)
case diffmatchpatch.DiffDelete:
removed += countLines(d.Text)
}
}
return
}
func colorDiff(orig, updated string) string {
dmp := diffmatchpatch.New()
diffs := dmp.DiffMain(orig, updated, false)
var b strings.Builder
for _, d := range diffs {
switch d.Type {
case diffmatchpatch.DiffInsert:
b.WriteString(`[green]` + tview.Escape(d.Text) + `[-]`)
case diffmatchpatch.DiffDelete:
b.WriteString(`[red]` + tview.Escape(d.Text) + `[-]`)
default:
b.WriteString(tview.Escape(d.Text))
}
}
return b.String()
}
func main() {
app := tview.NewApplication().EnablePaste(true)
leftArea := tview.NewTextArea()
leftArea.SetBorder(true)
leftArea.SetTitle(" Original (Lines: 0) ")
rightArea := tview.NewTextArea()
rightArea.SetBorder(true)
rightArea.SetTitle(" Updated (Lines: 0) ")
// Short, colored legend in the bottom panel title
bottom := tview.NewTextView().
SetDynamicColors(true).
SetChangedFunc(func() { app.Draw() })
bottom.SetBorder(true).SetTitle(` [red]Removed Lines[-] | [green]Added Lines[-] | Delete to Clear `)
updatePanels := func() {
origContent := leftArea.GetText()
updatedContent := rightArea.GetText()
leftArea.SetTitle(fmt.Sprintf(" Original (Lines: %d) ", countLines(origContent)))
rightArea.SetTitle(fmt.Sprintf(" Updated (Lines: %d) ", countLines(updatedContent)))
added, removed := diffLineCounts(origContent, updatedContent)
legend := fmt.Sprintf("[red]Removed Lines: %d[-] | [green]Added Lines: %d[-] | Delete to Clear", removed, added)
bottom.SetTitle(" " + legend + " ")
bottom.SetText(colorDiff(origContent, updatedContent))
}
leftArea.SetChangedFunc(updatePanels)
rightArea.SetChangedFunc(updatePanels)
flexTop := tview.NewFlex().
AddItem(leftArea, 0, 1, true).
AddItem(rightArea, 0, 1, false)
flex := tview.NewFlex().SetDirection(tview.FlexRow).
AddItem(flexTop, 0, 3, true).
AddItem(bottom, 0, 2, false)
// Instead of using a currentPane var and checking it in each area's SetInputCapture,
// just let tview handle focus naturally and react to delete on whichever pane has focus.
// We track last delete time for both panes for double-tap.
var lastDelTimeLeft, lastDelTimeRight time.Time
const doubleTapThreshold = 400 * time.Millisecond
leftArea.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
switch event.Key() {
case tcell.KeyTAB:
app.SetFocus(rightArea)
return nil
case tcell.KeyCtrlC, tcell.KeyEscape:
app.Stop()
return nil
case tcell.KeyDelete:
now := time.Now()
if now.Sub(lastDelTimeLeft) < doubleTapThreshold {
leftArea.SetText("", true)
rightArea.SetText("", true)
} else {
leftArea.SetText("", true)
}
lastDelTimeLeft = now
updatePanels()
return nil
}
return event
})
rightArea.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
switch event.Key() {
case tcell.KeyTAB:
app.SetFocus(leftArea)
return nil
case tcell.KeyCtrlC, tcell.KeyEscape:
app.Stop()
return nil
case tcell.KeyDelete:
now := time.Now()
if now.Sub(lastDelTimeRight) < doubleTapThreshold {
leftArea.SetText("", true)
rightArea.SetText("", true)
} else {
rightArea.SetText("", true)
}
lastDelTimeRight = now
updatePanels()
return nil
}
return event
})
// Global handler: TAB switches focus, Ctrl+C/Esc stops app, but delete is handled per pane.
app.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
switch event.Key() {
case tcell.KeyTAB:
if app.GetFocus() == leftArea {
app.SetFocus(rightArea)
} else {
app.SetFocus(leftArea)
}
return nil
case tcell.KeyCtrlC, tcell.KeyEscape:
app.Stop()
return nil
}
return event
})
app.SetFocus(leftArea)
updatePanels()
if err := app.SetRoot(flex, true).EnableMouse(true).Run(); err != nil {
panic(err)
}
}