xterm.js

Tested Software version 6.1.0-beta.302 on Linux. The xterm.js variant tested is the one shipped with Visual Studio Code’s integrated terminal. The homepage URL of this terminal is https://code.visualstudio.com/docs/terminal/basics. Full results available at ucs-detect repository path data/vscodeterminal.yaml.

xterm.js is a terminal multiplexer. These tests were executed in host terminal :ref:`ghostty. The homepage URL of this host terminal is https://ghostty.org/.

Score Breakdown

Detailed breakdown of how scores are calculated for xterm.js:

#	Score Type	Raw Score	Final Scaled Score
1	WIDE	29.25%	11.8%
2	NARROW	99.95%	99.9%
3	ZWJ	0.69%	0.7%
4	LANG	92.15%	92.1%
5	VS16	50.00%	50.0%
6	VS15	0.00%	(excluded)
7	SRI	0.00%	0.0%
8	SFZ	100.00%	100.0%
9	RI	100.00%	100.0%
10	FEAT	47.22%	47.2%
11	Graphics	0%	0.0%
12	Resources	N/A	N/A

Score Comparison Plot:

The following plot shows how this terminal’s scores compare to all other terminals tested.

Scaled scores comparison across all metrics (normalized 0-100%)

Final Scaled Score Calculation:

• Raw Final Score: 55.42% (weighted average: WIDE + NARROW + ZWJ + LANG + VS16 + 0.33 * SRI + 0.33 * SFZ + RI + CAP + 0.5 * GFX) the categorized ‘average’ absolute support level of this terminal.

  Note

  RSC (Resources) is a composite CPU, memory, and runtime score, displayed for comparison but excluded from the final score FEAT (Features) is the fraction of notable features supported. GFX (Graphics) scores 100% for modern protocols (iTerm2, Kitty), 50% for legacy only (Sixel, ReGIS), 0% for none.

• Final Scaled Score: 26.4% (normalized across all terminals tested). Final Scaled scores are normalized (0-100%) relative to all terminals tested

WIDE Score Details:

Wide character support calculation:

• Total successful contested codepoints: 148

• Total contested codepoints tested: 506

• Formula: 148 / 506

• Result: 29.25%

NARROW Score Details:

Narrow character support calculation:

• Total successful contested codepoints: 5592

• Total contested codepoints tested: 5595

• Formula: 5592 / 5595

• Result: 99.95%

ZWJ Score Details:

Emoji ZWJ (Zero-Width Joiner) support calculation:

• Total successful sequences: 10

• Total sequences tested: 1445

• Formula: 10 / 1445

• Result: 0.69%

VS16 Score Details:

Variation Selector-16 support calculation:

• Errors: 213 of 426 codepoints tested

• Success rate: 50.0%

• Formula: 50.0 / 100

• Result: 50.00%

Variation Selector-15 support:

Note

Interpretation of VS-15 is contested. Its width behavior is not consistently implemented across terminals; this measurement is informational and excluded from final scoring.

Variation Selector-15 support calculation:

• Errors: 158 of 158 codepoints tested

• Success rate: 0.0%

• Formula: 0.0 / 100

• Result: 0.00%

SRI Score Details:

Standalone Regional Indicator support calculation:

• Total successful codepoints: 0

• Total codepoints tested: 26

• Formula: 0 / 26

• Result: 0.00%

SFZ Score Details:

Standalone Fitzpatrick skin tone modifier support calculation:

• Total successful codepoints: 5

• Total codepoints tested: 5

• Formula: 5 / 5

• Result: 100.00%

RI Score Details:

Regional Indicator flag sequence support calculation:

• Total successful sequences: 262

• Total sequences tested: 262

• Formula: 262 / 262

• Result: 100.00%

Features Score Details:

Notable terminal features (8.5 / 18):

• Set bracketed paste mode (2004): yes

• Synchronized Output (2026): yes

• In-Band Window Resize Notifications (2048): no

• Send FocusIn/FocusOut events (1004): yes

• Enable SGR Mouse Mode (1006): yes

• Grapheme Clustering (2027): no

• Bracketed Paste MIME (5522): no

• Kitty Keyboard (Full): yes

• XTGETTCAP: no

• Text Sizing (OSC 66): no

• Tofu Detection: no

• Kitty Clipboard Protocol: no

• OSC 52 Clipboard: no

• Kitty Pointer Shapes (OSC 22): no

• Kitty Notifications (OSC 99): yes

• Color Report (OSC 10/11): yes

• Terminal Identification (XTVERSION): yes

• Truecolor Detection: partial

Raw score: 47.22%

Graphics Score Details:

Graphics protocol support (0%):

• Sixel: no

• ReGIS: no

• iTerm2: no

• Kitty: no

Scoring: 100% for modern (iTerm2/Kitty), 50% for legacy only (Sixel/ReGIS), 0% for none

Resource Score Details:

Resource profiling data not available.

LANG Score Details (Geometric Mean):

Geometric mean calculation:

• Formula: (p₁ × p₂ × … × pₙ)^(1/n) where n = 85 contested languages

• About geometric mean

• Result: 92.15%

Wide character support

Wide character support of xterm.js is 97.0% (1341 errors of 44568 codepoints tested).

Sequence of a WIDE character, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+00019044	‘\U00019044’	Cn	2	na

Total codepoints: 1

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x99\x81\x84|\\n12|\\n"
  𙁄|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 1.

Narrow character support

Narrow character support of xterm.js is 100.0% (3 errors of 36254 codepoints tested).

Sequence of a NARROW character, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0001F93B	‘\U0001f93b’	So	1	MODERN PENTATHLON

Total codepoints: 1

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x9f\xa4\xbb|\\n1|\\n"
  🤻|
  1|
  

• python wcwidth.wcswidth() measures width 1, while xterm.js measures width 2.

Emoji ZWJ support

Compatibility of xterm.js with the Unicode Emoji ZWJ sequence table is 0.7% (1435 errors of 1445 sequences tested).

Sequence of an Emoji ZWJ Sequence, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0001F3C3	‘\U0001f3c3’	So	2	RUNNER
2	U+0001F3FE	‘\U0001f3fe’	Sk	2	EMOJI MODIFIER FITZPATRICK TYPE-5
3	U+200D	‘\u200d’	Cf	0	ZERO WIDTH JOINER
4	U+2640	‘\u2640’	So	1	FEMALE SIGN
5	U+FE0F	‘\ufe0f’	Mn	0	VARIATION SELECTOR-16
6	U+200D	‘\u200d’	Cf	0	ZERO WIDTH JOINER
7	U+27A1	‘\u27a1’	So	1	BLACK RIGHTWARDS ARROW
8	U+FE0F	‘\ufe0f’	Mn	0	VARIATION SELECTOR-16

Total codepoints: 8

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x9f\x8f\x83\xf0\x9f\x8f\xbe\xe2\x80\x8d\xe2\x99\x80\xef\xb8\x8f\xe2\x80\x8d\xe2\x9e\xa1\xef\xb8\x8f|\\n12|\\n"
  🏃🏾‍♀️‍➡️|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 6.

Variation Selector-16 support

Emoji VS-16 results for xterm.js is 213 errors out of 426 total codepoints tested, 50.0% success. Sequence of a NARROW Emoji made WIDE by Variation Selector-16, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+2733	‘\u2733’	So	1	EIGHT SPOKED ASTERISK
2	U+FE0F	‘\ufe0f’	Mn	0	VARIATION SELECTOR-16

Total codepoints: 2

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe2\x9c\xb3\xef\xb8\x8f|\\n12|\\n"
  ✳️|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 1.

Variation Selector-15 support

Emoji VS-15 results for xterm.js is 158 errors out of 158 total codepoints tested, 0.0% success. Sequence of a WIDE Emoji made NARROW by Variation Selector-15, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0001F3AE	‘\U0001f3ae’	So	2	VIDEO GAME
2	U+FE0E	‘\ufe0e’	Mn	0	VARIATION SELECTOR-15

Total codepoints: 2

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x9f\x8e\xae\xef\xb8\x8e|\\n1|\\n"
  🎮︎|
  1|
  

• python wcwidth.wcswidth() measures width 1, while xterm.js measures width 2.

Standalone Regional Indicator support

Standalone Regional Indicator support of xterm.js is 0.0% (26 errors of 26 codepoints tested).

Sequence of a standalone Regional Indicator, from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0001F1F3	‘\U0001f1f3’	So	2	REGIONAL INDICATOR SYMBOL LETTER N

Total codepoints: 1

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x9f\x87\xb3|\\n12|\\n"
  🇳|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 1.

Standalone Fitzpatrick modifier support

Standalone Fitzpatrick skin tone modifier support of xterm.js is 100.0% (0 errors of 5 codepoints tested).

Regional Indicator flag sequence support

Regional Indicator flag sequence support of xterm.js is 100.0% (0 errors of 262 sequences tested).

Graphics Protocol Support

xterm.js does not report support for any graphics protocols.

Note: Must be enabled with "terminal.integrated.enableImages": true.

Detection Methods:

• Sixel and ReGIS: Not detected via the Device Attributes (DA1) query CSI c (\x1b[c). Sixel indicator (4): not present, ReGIS indicator (3): not present.

• Kitty graphics: Not detected by sending a Kitty graphics query and checking for an OK response.

• iTerm2 inline images: Not detected by drawing a 1x1 transparent image, OSC 1337 ; File=inline=1, and checking that the cursor advanced a single column.

• iTerm2 capabilities: Not detected via the OSC 1337 ; Capabilities query, which does not describe image support, and does not contribute to this score.

Device Attributes

• Raw response: '\x1b[?1;2c'

• Service class: 1 (VT100)

Detected Extensions:

Code	Description
2	Printer port

Language Support

The following 98 languages were tested with 100% success:

(Jinan), (Yeonbyeon), Aja, Amarakaeri, Arabic, Standard, Assyrian Neo-Aramaic, Baatonum, Bamun, Belanda Viri, Bora, Catalan (2), Chickasaw, Chinantec, Chiltepec, Chinese, Gan, Chinese, Hakka, Chinese, Jinyu, Chinese, Mandarin (Beijing), Chinese, Mandarin (Guiyang), Chinese, Mandarin (Harbin), Chinese, Mandarin (Nanjing), Chinese, Mandarin (Simplified), Chinese, Mandarin (Tianjin), Chinese, Mandarin (Traditional), Chinese, Min Nan, Chinese, Wu, Chinese, Xiang, Chinese, Yue, Colorado, Dagaare, Southern, Dangme, Dari, Dendi, Dinka, Northeastern, Ditammari, Dzongkha, Evenki, Farsi, Western, Fon, French (Welche), Fur, Ga, Gen, Gilyak, Gumuz, Japanese, Japanese (Osaka), Japanese (Tokyo), Kabyle, Korean, Lamnso’, Lao, Lingala (tones), Maldivian, Maori (2), Mazahua Central, Mirandese, Mixtec, Metlatónoc, Mongolian, Halh (Mongolian), Mòoré, Nanai, Navajo, Nuosu, Orok, Otomi, Mezquital, Panjabi, Eastern, Panjabi, Western, Pashto, Northern, Picard, Pular (Adlam), Saint Lucian Creole French, Secoya, Seraiki, Shan, Shipibo-Conibo, Sinhala, Siona, South Azerbaijani, Tagalog (Tagalog), Tai Dam, Tamazight, Central Atlas, Tamil, Tamil (Sri Lanka), Tem, Thai, Thai (2), Tibetan, Central, Ticuna, Uduk, Urdu, Urdu (2), Veps, Vietnamese, Vietnamese (Han nom), Waama, Yaneshaʼ, Yiddish, Eastern, Yoruba, Éwé.

The following 20 languages are not fully supported:

lang	n_errors	n_total	pct_success
Javanese (Javanese)	321	530	39.4%
Sanskrit	145	493	70.6%
Malayalam	247	844	70.7%
Bengali	96	385	75.1%
Marathi	86	391	78.0%
Hindi	82	390	79.0%
Sanskrit (Grantha)	61	293	79.2%
Khmer, Central	90	443	79.7%
Maithili	71	357	80.1%
Nepali	69	352	80.4%
Khün	74	419	82.3%
Tamang, Eastern	11	70	84.3%
Gujarati	50	343	85.4%
Magahi	43	314	86.3%
Bhojpuri	41	313	86.9%
Telugu	42	384	89.1%
Kannada	14	287	95.1%
Chakma	13	267	95.1%
Burmese	10	268	96.3%
Mon	7	332	97.9%

Javanese (Javanese)

Sequence of language Javanese (Javanese) from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+A98F	‘\ua98f’	Lo	1	JAVANESE LETTER KA
2	U+A9BA	‘\ua9ba’	Mc	0	JAVANESE VOWEL SIGN TALING
3	U+A9B4	‘\ua9b4’	Mc	0	JAVANESE VOWEL SIGN TARUNG

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xea\xa6\x8f\xea\xa6\xba\xea\xa6\xb4|\\n12|\\n"
  ꦏꦺꦴ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Sanskrit

Sequence of language Sanskrit from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Malayalam

Sequence of language Malayalam from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0D15	‘\u0d15’	Lo	1	MALAYALAM LETTER KA
2	U+0D4D	‘\u0d4d’	Mn	0	MALAYALAM SIGN VIRAMA
3	U+0D15	‘\u0d15’	Lo	1	MALAYALAM LETTER KA
4	U+0D3E	‘\u0d3e’	Mc	0	MALAYALAM VOWEL SIGN AA

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xb4\x95\xe0\xb5\x8d\xe0\xb4\x95\xe0\xb4\xbe|\\n12|\\n"
  ക്കാ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Bengali

Sequence of language Bengali from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0995	‘\u0995’	Lo	1	BENGALI LETTER KA
2	U+09BF	‘\u09bf’	Mc	0	BENGALI VOWEL SIGN I
3	U+0982	‘\u0982’	Mc	0	BENGALI SIGN ANUSVARA

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa6\x95\xe0\xa6\xbf\xe0\xa6\x82|\\n12|\\n"
  কিং|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Marathi

Sequence of language Marathi from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Hindi

Sequence of language Hindi from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Sanskrit (Grantha)

Sequence of language Sanskrit (Grantha) from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+00011315	‘\U00011315’	Lo	1	GRANTHA LETTER KA
2	U+0001133E	‘\U0001133e’	Mc	0	GRANTHA VOWEL SIGN AA
3	U+00011302	‘\U00011302’	Mc	0	GRANTHA SIGN ANUSVARA

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x91\x8c\x95\xf0\x91\x8c\xbe\xf0\x91\x8c\x82|\\n12|\\n"
  𑌕𑌾𑌂|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Khmer, Central

Sequence of language Khmer, Central from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+1780	‘\u1780’	Lo	1	KHMER LETTER KA
2	U+17D2	‘\u17d2’	Mn	0	KHMER SIGN COENG
3	U+178A	‘\u178a’	Lo	1	KHMER LETTER DA
4	U+17C5	‘\u17c5’	Mc	0	KHMER VOWEL SIGN AU

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe1\x9e\x80\xe1\x9f\x92\xe1\x9e\x8a\xe1\x9f\x85|\\n12|\\n"
  ក្ដៅ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Maithili

Sequence of language Maithili from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Nepali

Sequence of language Nepali from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Khün

Sequence of language Khün from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+1A20	‘\u1a20’	Lo	1	TAI THAM LETTER HIGH KA
2	U+1A6E	‘\u1a6e’	Mc	0	TAI THAM VOWEL SIGN E
3	U+1A60	‘\u1a60’	Mn	0	TAI THAM SIGN SAKOT
4	U+1A2F	‘\u1a2f’	Lo	1	TAI THAM LETTER DA
5	U+1A68	‘\u1a68’	Mn	0	TAI THAM VOWEL SIGN UUE

Total codepoints: 5

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe1\xa8\xa0\xe1\xa9\xae\xe1\xa9\xa0\xe1\xa8\xaf\xe1\xa9\xa8|\\n12|\\n"
  ᨠᩮ᩠ᨯᩨ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Tamang, Eastern

Sequence of language Tamang, Eastern from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Gujarati

Sequence of language Gujarati from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0A95	‘\u0a95’	Lo	1	GUJARATI LETTER KA
2	U+0ACD	‘\u0acd’	Mn	0	GUJARATI SIGN VIRAMA
3	U+0A95	‘\u0a95’	Lo	1	GUJARATI LETTER KA
4	U+0ABE	‘\u0abe’	Mc	0	GUJARATI VOWEL SIGN AA

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xaa\x95\xe0\xab\x8d\xe0\xaa\x95\xe0\xaa\xbe|\\n12|\\n"
  ક્કા|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Magahi

Sequence of language Magahi from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0924	‘\u0924’	Lo	1	DEVANAGARI LETTER TA
4	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xa4\xe0\xa4\xbf|\\n12|\\n"
  क्ति|
  12|
  

Bhojpuri

Sequence of language Bhojpuri from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0915	‘\u0915’	Lo	1	DEVANAGARI LETTER KA
2	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
3	U+0918	‘\u0918’	Lo	1	DEVANAGARI LETTER GHA
4	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA
5	U+0918	‘\u0918’	Lo	1	DEVANAGARI LETTER GHA
6	U+093F	‘\u093f’	Mc	0	DEVANAGARI VOWEL SIGN I
7	U+094D	‘\u094d’	Mn	0	DEVANAGARI SIGN VIRAMA

Total codepoints: 7

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\x98\xe0\xa5\x8d\xe0\xa4\x98\xe0\xa4\xbf\xe0\xa5\x8d|\\n12|\\n"
  क्घ्घि्|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 4.

Telugu

Sequence of language Telugu from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0C15	‘\u0c15’	Lo	1	TELUGU LETTER KA
2	U+0C41	‘\u0c41’	Mc	0	TELUGU VOWEL SIGN U
3	U+0C02	‘\u0c02’	Mc	0	TELUGU SIGN ANUSVARA

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xb0\x95\xe0\xb1\x81\xe0\xb0\x82|\\n12|\\n"
  కుం|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Kannada

Sequence of language Kannada from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+0C95	‘\u0c95’	Lo	1	KANNADA LETTER KA
2	U+0CBE	‘\u0cbe’	Mc	0	KANNADA VOWEL SIGN AA
3	U+0C82	‘\u0c82’	Mc	0	KANNADA SIGN ANUSVARA

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe0\xb2\x95\xe0\xb2\xbe\xe0\xb2\x82|\\n12|\\n"
  ಕಾಂ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Chakma

Sequence of language Chakma from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+00011107	‘\U00011107’	Lo	1	CHAKMA LETTER KAA
2	U+00011133	‘\U00011133’	Mn	0	CHAKMA VIRAMA
3	U+00011120	‘\U00011120’	Lo	1	CHAKMA LETTER YYAA
4	U+0001112C	‘\U0001112c’	Mc	0	CHAKMA VOWEL SIGN E

Total codepoints: 4

• Shell test using printf(1), '|' should align in output:

  $ printf "\xf0\x91\x84\x87\xf0\x91\x84\xb3\xf0\x91\x84\xa0\xf0\x91\x84\xac|\\n12|\\n"
  𑄇𑄳𑄠𑄬|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Burmese

Sequence of language Burmese from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+1000	‘\u1000’	Lo	1	MYANMAR LETTER KA
2	U+103B	‘\u103b’	Mc	0	MYANMAR CONSONANT SIGN MEDIAL YA
3	U+1031	‘\u1031’	Mc	0	MYANMAR VOWEL SIGN E

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe1\x80\x80\xe1\x80\xbb\xe1\x80\xb1|\\n12|\\n"
  ကျေ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

Mon

Sequence of language Mon from midpoint of alignment failure records:

#	Codepoint	Python	Category	wcwidth	Name
1	U+1007	‘\u1007’	Lo	1	MYANMAR LETTER JA
2	U+103C	‘\u103c’	Mc	0	MYANMAR CONSONANT SIGN MEDIAL RA
3	U+1031	‘\u1031’	Mc	0	MYANMAR VOWEL SIGN E

Total codepoints: 3

• Shell test using printf(1), '|' should align in output:

  $ printf "\xe1\x80\x87\xe1\x80\xbc\xe1\x80\xb1|\\n12|\\n"
  ဇြေ|
  12|
  

• python wcwidth.wcswidth() measures width 2, while xterm.js measures width 3.

DEC Private Modes Support

DEC private modes results for xterm.js: 4 changeable modes of 4 supported out of 8 total modes tested (50.0% support, 50.0% changeable).

Complete list of DEC private modes tested:

Mode	Name	Description	Supported	Changeable	Enabled
1004	FOCUS_IN_OUT_EVENTS	Send FocusIn/FocusOut events	Yes	Yes	No
1006	MOUSE_EXTENDED_SGR	Enable SGR Mouse Mode	Yes	Yes	No
2004	BRACKETED_PASTE	Set bracketed paste mode	Yes	Yes	No
2026	SYNCHRONIZED_OUTPUT	Synchronized Output	Yes	Yes	No
2027	GRAPHEME_CLUSTERING	Grapheme Clustering	No	No	No
2031	COLOR_PALETTE_UPDATES	Color palette updates	No	No	No
2048	IN_BAND_WINDOW_RESIZE	In-Band Window Resize Notifications	No	No	No
5522	BRACKETED_PASTE_MIME	Bracketed Paste MIME	No	No	No

Summary: 4 changeable, 4 not changeable.

Kitty Keyboard Protocol

xterm.js supports the Kitty keyboard protocol.

#	Flag	Key	Supported
1	Disambiguate escape codes	disambiguate	Yes
2	Report event types	report_events	Yes
3	Report alternate keys	report_alternates	Yes
4	Report all keys as escape codes	report_all_keys	Yes
5	Report associated text	report_text	Yes

Detection is performed by enabling all progressive enhancement modes by set (CSI = 31 ; 1 u) and re-querying with CSI ? u to confirm which modes the terminal honors, before restoring its original flags.

XTGETTCAP (Terminfo Capabilities)

xterm.js does not support the XTGETTCAP sequence.

Text Sizing Protocol (OSC 66)

xterm.js does not support the Text Sizing protocol.

Tofu Detection

A tofu is the □ U+25A1 WHITE SQUARE placeholder box drawn in place of a codepoint the terminal’s font has no glyph for. Two protocols allow a program to ask which codepoints may ‘tofu’: mintty’s Font Glyph Coverage Enquiry and the Glyph Protocol implemented first by Rio.

xterm.js does not answer a font glyph coverage enquiry by either protocol, ‘tofus’ cannot be determined by automatic code.

Truecolor Support

xterm.js supports 24-bit truecolor, detectable via:

• XTGETTCAP (RGB capability): no

• DECRQSS (truecolor probe): no

• COLORTERM: yes (truecolor)

Warning

COLORTERM is an environment variable, not a terminal query. It is not forwarded over SSH without SendEnv / AcceptEnv configuration, so detection via COLORTERM alone may be unreliable on remote hosts.

OSC 52 Clipboard Support

xterm.js does not advertise OSC 52 clipboard support via DA1 extension 52 or XTGETTCAP Ms.

• DA1 extension 52: no

• XTGETTCAP Ms: no

Terminal Identification

xterm.js is identified as xterm.js version 6.1.0-beta.302 (detected via XTVERSION).

• XTVERSION (raw): xterm.js(6.1.0-beta.302)

• XTVERSION: yes

• XTGETTCAP TN: no

• ENQ: no

• TERM_PROGRAM: yes (vscode)

• TERM: no (xterm-256color) (inherited from host terminal)

Reproduction

To reproduce these results for xterm.js, install and run ucs-detect with the following commands:

uvx ucs-detect --rerun data/vscodeterminal.yaml

Test Performance

Performance data for xterm.js is not available.