mirror of
https://github.com/rstudio/shiny.git
synced 2026-04-29 03:00:45 -04:00
fa200022c5
* Use more markdown/roxygen2 tags * Pull isTruthy out into own file * Rewrite validate for clarity
39 lines
1.3 KiB
R
39 lines
1.3 KiB
R
% Generated by roxygen2: do not edit by hand
|
|
% Please edit documentation in R/utils.R
|
|
\name{isTruthy}
|
|
\alias{isTruthy}
|
|
\title{Truthy and falsy values}
|
|
\usage{
|
|
isTruthy(x)
|
|
}
|
|
\arguments{
|
|
\item{x}{An expression whose truthiness value we want to determine}
|
|
}
|
|
\description{
|
|
The terms "truthy" and "falsy" generally indicate whether a value, when
|
|
coerced to a \code{\link[base:logical]{base::logical()}}, is \code{TRUE} or \code{FALSE}. We use
|
|
the term a little loosely here; our usage tries to match the intuitive
|
|
notions of "Is this value missing or available?", or "Has the user provided
|
|
an answer?", or in the case of action buttons, "Has the button been
|
|
clicked?".
|
|
}
|
|
\details{
|
|
For example, a \code{textInput} that has not been filled out by the user has
|
|
a value of \code{""}, so that is considered a falsy value.
|
|
|
|
To be precise, a value is truthy \emph{unless} it is one of:
|
|
\itemize{
|
|
\item \code{FALSE}
|
|
\item \code{NULL}
|
|
\item \code{""}
|
|
\item An empty atomic vector
|
|
\item An atomic vector that contains only missing values
|
|
\item A logical vector that contains all \code{FALSE} or missing values
|
|
\item An object of class \code{"try-error"}
|
|
\item A value that represents an unclicked \code{\link[=actionButton]{actionButton()}}
|
|
}
|
|
|
|
Note in particular that the value \code{0} is considered truthy, even though
|
|
\code{as.logical(0)} is \code{FALSE}.
|
|
}
|