| Title | Lightweight Tables via JSON Specs and JavaScript |
| Version | 0.0.13 |
| Description | A lightweight grammar of tables. Build a table by declaring a JSON spec (titles, spanners, row groups, footnotes, formatters, etc.); a tiny vanilla JavaScript runtime builds the HTML table from the spec on page load. No sass, no V8, no htmlwidgets — just base R and xfun (htmltools is used only for the optional Shiny binding). |
| Depends | R (>= 4.1.0) |
| Imports | xfun (>= 0.57) |
| Suggests | htmltools, knitr, litedown, repr, shiny, testit |
| License | MIT + file LICENSE |
| URL | https://github.com/yihui/lt |
| BugReports | https://github.com/yihui/lt/issues |
| Author | Yihui Xie  [aut, cre, cph] |
Lightweight tables for R, inspired by gt.
lt provides a small grammar of tables that covers the structure most reports need — titles, column spanners, row groups, footnotes, and number formatting — without the heavy dependency stack. It targets HTML only (no LaTeX or RTF), which keeps the implementation minimal: the entire runtime is a single vanilla-JS file (under 10 KB minified).
1 Example
library(lt)
d = data.frame(
Group = c("Treatment", "Treatment", "Control", "Control"),
Endpoint = c("Primary", "Secondary", "Primary", "Secondary"),
Estimate = c(0.6123, 0.7891, 0.4567, 0.5432),
CI_Lower = c(0.4012, 0.5678, 0.2345, 0.3210),
CI_Upper = c(0.8234, 1.0104, 0.6789, 0.7654),
P_Value = c(0.0012, 0.0456, 0.1234, 0.2345)
)
lt(d) |>
lt_group(~ Group) |>
lt_header("Study Results", "Primary and secondary endpoints") |>
lt_spanner(`95% CI` ~ CI_Lower + CI_Upper) |>
lt_format(~ Estimate + CI_Lower + CI_Upper, decimals = 3) |>
lt_format(~ P_Value, decimals = 4) |>
lt_footnote("Two-sided p-value from log-rank test.", "column", ~ P_Value)
More examples at https://pkg.yihui.org/lt/examples.html.
2 Installation
remotes::install_github("yihui/lt")
3 Acknowledgements
This package was written with the help of Claude Code. While I have verified that it does not directly copy code from other projects, I do not have a clear picture of whether it may have indirectly reused open-source code. If you discover any code in this package that appears to originate from another project, please file an issue and I will check whether the license is compatible and the original authors are properly attributed.
lt is directly inspired by gt by Rich Iannone and the RStudio/Posit team. The grammar of tables that gt pioneered — layering titles, spanners, footnotes, and formatters onto a data frame — is a great idea; lt aims to provide a minimal re-implementation for contexts where a lighter footprint is preferred.
4 Status
Alpha. The first goal — feature parity with what gsDesign2::as_gt()
needs (HTML output only) — is reached. We now look to the
R Tables for Regulatory Submissions
work to cover what clinical-trial TLFs typically need: column merging,
row indentation, value substitution, and column hiding are in place.
Appendix
To cite the package lt in publications, please use:
Xie Y (2026). lt: Lightweight Tables via JSON Specs and JavaScript. R package version 0.0.13, https://github.com/yihui/lt.
@Manual{,
title = {lt: Lightweight Tables via JSON Specs and JavaScript},
author = {Yihui Xie},
year = {2026},
note = {R package version 0.0.13},
url = {https://github.com/yihui/lt},
}