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Merged
Sarthak160 merged 4 commits into from
Aug 19, 2025
Merged

feat: truncate string values and add ellipsis #24

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0b12171
feat: truncate string values and add ellipsis
ayush3160 Aug 11, 2025
1fa8e40
fix: added truncation with plain text responses also
ayush3160 Aug 11, 2025
4386ef2
chore: addressed copilot comments
ayush3160 Aug 11, 2025
8ecf85d
fix: unit tests
ayush3160 Aug 18, 2025
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22 changes: 12 additions & 10 deletions jsonDiff_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -428,11 +428,13 @@ func TestSprintJSONDiff(t *testing.T) {
"49bec237abb42a872e82edee006cb72e8270b4c14179140ce03ebc47ad36fa2d",
"3cd84203cf23bffc56c12344c2b2fbf313c1e4ed34f125ea813a50b42adca1d9",
"825c067292a1b5ce6ce1724c52fa2068bfb651a35273a65351be3e63d8614df1",
"3bf543c95d44ce58e0005887bd44c4ab27d00a0bc1355fd23db30f5ba659a0d1",
},
expectedStringB: []string{
"f3603f2c454c9d81d8cc19296af4e4aff906d102263beea5af3892c223d0ef29",
"c25b5b827481d888a7a5551ee05d6ea4590d59d2674fb5182394f13c3adca29a",
"d2f1d7f7dcea6764caeab964e34a99e936715959cc066ebd77822bb5daa80316",
"beaa58fc7489cf3e180eca7d4ddd2fb5cacaf740df8ecc0b5f822b8a4b3d0c9d",
},
json1: "{\"longKey\":\"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\",\"nested\":{\"key1\":{\"subkey1\":\"value1\"},\"key2\":{\"subkey2\":\"value2\"}}}",
json2: "{\"longKey\":\"bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\",\"nested\":{\"key1\":{\"subkey1\":\"value1\"},\"key2\":{\"subkey2\":\"value3\"}}}",
Expand Down Expand Up @@ -462,10 +464,10 @@ func TestSprintJSONDiff(t *testing.T) {
},
{
expectedStringA: []string{
"c9a069dd6d3aaf5052219992d43c57f00d66881849a0004df66ca44d4bcab74d",
"9cac2220ac73f8abd3a13d9fbc4249bd481f0188590a26e87f87d354078c9dfa",
},
expectedStringB: []string{
"b6a5cc8d3ef65269d1c729f769d2e64fb501e545b2d2f3306d0359211220b242",
"ea18ec7619618dd08777bf00afd74100cf0ae6ea4f914bd26417621b9419a3b8",
},
json1: "{\"paragraph\":\"This is a long paragraph with many words. The quick brown fox jumps over the lazy dog. A random word will change in the middle of this sentence.\"}",
json2: "{\"paragraph\":\"This is a long paragraph with many words. The quick brown fox jumps over the lazy dog. A random word will change in the middle of this phrase.\"}",
Expand All @@ -484,10 +486,10 @@ func TestSprintJSONDiff(t *testing.T) {
},
{
expectedStringA: []string{
"2882d548db56674bf1d45dc423178c66c7dbcc3f7e72d5c2edca479cda04180c",
"56a9a0b500759fdb334d3977aac390d18c11fb8e5e10d269ff8f65e034604ea7",
},
expectedStringB: []string{
"9fe5ef3cbbc2103ec21ddf9497a5edba97e546d27f08cad456f208352bf5bc8d",
"546b08086b296dc7df590f37e5afb965ed58c129fcc09800bca7416a41515e34",
},
json1: "{\"longKey\":\"This is a long key with many words and a subtle change at the end of this sentence.\"}",
json2: "{\"longKey\":\"This is a long key with many words and a subtle change at the end of this phrase.\"}",
Expand All @@ -506,10 +508,10 @@ func TestSprintJSONDiff(t *testing.T) {
},
{
expectedStringA: []string{
"563c5a6b903195cf1e4d408c265edd57ca2f97d818db6ea0b688f30d7b642128",
"d190663b3f566e3fc02a1fb599851f1debda96ebf0fdc14e111e52149a99cf25",
},
expectedStringB: []string{
"2e340d7201d7bfbcf9dd8181407fbcbccf993b9b9150bc91c824a17421fb5087",
"b0722e878e6f8d4ba5b7bd6ccb1cca44e38d6f9f2e102d23badb4f4e1cae5852",
},
json1: "{\"level1\":{\"level2\":{\"level3\":{\"longKey\":\"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjp7ImlkIjoxLCJmaXJzdE5hbWUiOiJTdGVybGluZyIsImxhc3ROYW1lIjoiU2F1ZXIiLCJlbWFpbCI6Ik1hc29uLkdvbGRuZXI0OUBob3RtYWlsLmNvbSIsInBhc3N3b3JkIjoiZGFhOTMyMGY1YzU4NDRiODRiMjhlMDE2YjRiOGM0MGIiLCJjcmVhdGVkQXQiOiIyMDIzLTEyLTA4VDE4OjE2OjQxLjYzOFoiLCJ1cGRhdGVkQXQiOm51bGwsImRlbGV0ZWRBdCI6bnVsbH0sImlhdCI6MTcxOTM0MzYzOCwiZXhwIjoxNzE5NDMwMDM4fQ.Kgm3Lmbg97M_QQP5Gn9q4suRYEF7_n4ITqehV4i7t_s is a very long value with many descriptive words and phrases to make it lengthy.\"}}}}",
json2: "{\"level1\":{\"level2\":{\"level3\":{\"longKey\":\"This is a very long value with many descriptive words and phrases to make it extensive.\"}}}}",
Expand All @@ -528,9 +530,9 @@ func TestSprintJSONDiff(t *testing.T) {
},
{
expectedStringA: []string{
"b0d3af312d652a356588bdcddd6f8560cd7700e3532f69405df5dd555b9b1516",
"9776cf81505093952b85a8885cd84a713dfdbfc1367ab77de74c066c2d767678",
},
expectedStringB: []string{"7bac2737756e4613e655b7654087d8467cce2eb039f549c66bd5e1572d9c3a46"},
expectedStringB: []string{"c652c8abb9793fc7073a55f9c5126b92a486afd7aadb194397ea88ff09582cfc"},
json1: "{\"level1\":{\"level2\":{\"level3\":{\"longKeyWithMinorChangeA\":\"This is a very long value that remains mostly the same.\"}}}}",
json2: "{\"level1\":{\"level2\":{\"level3\":{\"longKeyWithMinorChangeB\":\"This is a very long value that remains mostly the same.\"}}}}",
name: "long nested structures with slight key changes",
Expand All @@ -548,9 +550,9 @@ func TestSprintJSONDiff(t *testing.T) {
},
{
expectedStringA: []string{
"67e2232cc42a9f92d7c6871d33a768ed9f7858eb22a00a52f593c1b163eced21",
"2cf4331f583b813f6d368fd604c582f860eff645fe98541396095a52d08bf635",
},
expectedStringB: []string{"59c1bfd3866bc77553c17703b6f5bc69a13c46fba093f6dd09c1d14c15b5a4e7"},
expectedStringB: []string{"e8916e02d1a0f3b95983c52e67b122d18f8f7c12f36877bc08e66fdbc841605e"},
json1: "{\"nested\":{\"longParagraph\":\"This is a long paragraph. It contains multiple sentences. Each sentence has many words. One sentence will be different in the second JSON.\"}}",
json2: "{\"nested\":{\"longParagraph\":\"This is a long paragraph. It contains multiple sentences. Each sentence has many words. One phrase will be different in the second JSON.\"}}",
name: "long paragraphs with nested arrays and maps",
Expand Down
157 changes: 146 additions & 11 deletions jsondiff.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ import (
"regexp"
"sort"
"strings"
"unicode/utf8"

"github.com/fatih/color"
"github.com/tidwall/gjson"
Expand All @@ -19,6 +20,8 @@ type colorRange struct {
End int // End is the ending index of the range.
}

const maxCharactersLength = 30

// Diff holds the colorized differences between the expected and actual JSON responses.
// Expected: The colorized string representing the differences in the expected JSON response.
// Actual: The colorized string representing the differences in the actual JSON response.
Expand Down Expand Up @@ -61,8 +64,8 @@ func CompareJSON(expectedJSON []byte, actualJSON []byte, noise map[string][]stri
highlightActual := color.FgHiGreen

return Diff{
Expected: breakSliceWithColor(expectedJSONString, &highlightExpected, offset),
Actual: breakSliceWithColor(actualJSONString, &highlightActual, offset),
Expected: truncateStringWithEllipsis(breakSliceWithColor(expectedJSONString, &highlightExpected, offset), highlightExpected),
Actual: truncateStringWithEllipsis(breakSliceWithColor(actualJSONString, &highlightActual, offset), highlightActual),
}, nil
}

Expand Down Expand Up @@ -111,8 +114,8 @@ func Compare(expectedJSON, actualJSON string) Diff {
highlightActual := color.FgHiGreen

// Colorize the differences in the expected and actual JSON strings.
colorizedExpected := breakSliceWithColor(expectedJSON, &highlightExpected, offsetExpected)
colorizedActual := breakSliceWithColor(actualJSON, &highlightActual, offsetActual)
colorizedExpected := truncateStringWithEllipsis(breakSliceWithColor(expectedJSON, &highlightExpected, offsetExpected), highlightExpected)
colorizedActual := truncateStringWithEllipsis(breakSliceWithColor(actualJSON, &highlightActual, offsetActual), highlightActual)

// Return the colorized differences in a Diff struct.
return Diff{
Expand Down Expand Up @@ -247,10 +250,13 @@ func writeKeyValuePair(builder *strings.Builder, key string, value interface{},

builder.WriteString(fmt.Sprintf("%s\"%s\": %s,\n", indent, key, formattedValue))
default:

serializedValue, _ := json.MarshalIndent(value, "", " ")
formattedValue := string(serializedValue)

if len(string(serializedValue)) > maxCharactersLength {
formattedValue = string(serializedValue[:maxCharactersLength]) + "..."
}

// Check if a color function is provided and the value is not empty.
if applyColor != nil && value != "" {
formattedValue = applyColor(formattedValue)
Expand Down Expand Up @@ -425,13 +431,13 @@ func compare(key string, val1, val2 interface{}, indent string, expect, actual *
return
}
// Colorize the differences in the values
c := color.FgRed
redColor := color.FgRed
offsetsStr1, offsetsStr2, _ := diffArrayRange(string(val1Str), string(val2Str))
expectDiff := breakSliceWithColor(string(val1Str), &c, offsetsStr1)
c = color.FgGreen
actualDiff := breakSliceWithColor(string(val2Str), &c, offsetsStr2)
expect.WriteString(breakLines(fmt.Sprintf("%s\"%s\": %s,\n", indent, key, string(expectDiff))))
actual.WriteString(breakLines(fmt.Sprintf("%s\"%s\": %s,\n", indent, key, string(actualDiff))))
expectDiff := breakSliceWithColor(string(val1Str), &redColor, offsetsStr1)
greenColor := color.FgGreen
actualDiff := breakSliceWithColor(string(val2Str), &greenColor, offsetsStr2)
expect.WriteString(breakLines(fmt.Sprintf("%s\"%s\": %s,\n", indent, key, truncateStringWithEllipsis(string(expectDiff), redColor))))
actual.WriteString(breakLines(fmt.Sprintf("%s\"%s\": %s,\n", indent, key, truncateStringWithEllipsis(string(actualDiff), greenColor))))
return
}
// If values are equal, write the value without color
Expand Down Expand Up @@ -813,6 +819,135 @@ func truncateToMatchWithEllipsis(expectedText, actualText string) (string, strin
return truncatedExpected, truncatedActual
}

// truncateStringWithEllipsis truncates a string to a specified length, adding an ellipsis if necessary.
func truncateStringWithEllipsis(val string, c color.Attribute) string {
if !ansiRegex.MatchString(val) {
return truncatePlain(val, maxCharactersLength, "...")
}

colorEllipsis := color.New(c).Sprint("...")

type ansiRange struct{ Start, End int }
ranges := collectANSISegments(val)

// NEW: coalesce adjacent runs (or runs separated only by whitespace)
coalesced := make([]ansiRange, 0, len(ranges))
for _, r := range ranges {
if len(coalesced) == 0 {
coalesced = append(coalesced, r)
continue
}
last := &coalesced[len(coalesced)-1]
gap := val[last.End:r.Start]
if strings.TrimSpace(gap) == "" {
// merge into one big block (includes the whitespace gap)
last.End = r.End
} else {
coalesced = append(coalesced, r)
}
}

var out strings.Builder
prev := 0
for _, r := range coalesced {
out.WriteString(truncatePlain(val[prev:r.Start], maxCharactersLength, "..."))
out.WriteString(truncateANSISegment(val[r.Start:r.End], maxCharactersLength, colorEllipsis))
prev = r.End
}
out.WriteString(truncatePlain(val[prev:], maxCharactersLength, "..."))
return out.String()
}

// collectANSISegments collects segments of ANSI escape codes from the input string.
func collectANSISegments(s string) []struct{ Start, End int } {
var res []struct{ Start, End int }

in := false
segStart := 0
ms := ansiRegex.FindAllStringIndex(s, -1)
for _, m := range ms {
code := s[m[0]:m[1]]
if !in {
if code != ansiResetCode {
in = true
segStart = m[0]
}
} else {
if code == ansiResetCode {
res = append(res, struct{ Start, End int }{Start: segStart, End: m[1]})
in = false
}
}
}
if in { // unclosed color
res = append(res, struct{ Start, End int }{Start: segStart, End: len(s)})
}
return res
}

func truncatePlain(s string, limit int, ellipsis string) string {
if utf8.RuneCountInString(s) <= limit {
return s
}
cut := byteIndexAfterNRunes(s, limit)
return s[:cut] + ellipsis
}

func truncateANSISegment(seg string, limit int, coloredEllipsis string) string {
hasReset := strings.Contains(seg, ansiResetCode)
ms := ansiRegex.FindAllStringIndex(seg, -1)

var b strings.Builder
pos, mi, visible := 0, 0, 0

for pos < len(seg) && visible < limit {
if mi < len(ms) && pos == ms[mi][0] {
b.WriteString(seg[ms[mi][0]:ms[mi][1]])
pos = ms[mi][1]
mi++
continue
}
_, sz := utf8.DecodeRuneInString(seg[pos:])
b.WriteString(seg[pos : pos+sz])
pos += sz
visible++
}

if visible >= limit && moreVisibleAhead(seg, pos, ms, mi) {
b.WriteString(coloredEllipsis)
}
if hasReset && !strings.HasSuffix(b.String(), ansiResetCode) {
b.WriteString(ansiResetCode)
}
return b.String()
}

func moreVisibleAhead(s string, pos int, ms [][]int, mi int) bool {
for pos < len(s) {
if mi < len(ms) && pos == ms[mi][0] {
pos = ms[mi][1]
mi++
continue
}
return true
}
return false
}

func byteIndexAfterNRunes(s string, n int) int {
if n <= 0 {
return 0
}
count := 0
for i := range s {
if count == n {
return i
}
count++
}
return len(s)
}

// compareAndColorizeMaps compares two maps and returns the differences as colorized strings.
// a: The first map to compare.
// b: The second map to compare.
Expand Down
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