Jump to headingdeprecate<T extends Function>(fn: T,msg: string,code?: string,): T
The util.deprecate()
method wraps fn
(which may be a function or class) in
such a way that it is marked as deprecated.
import util from 'node:util';
exports.obsoleteFunction = util.deprecate(() => {
// Do something here.
}, 'obsoleteFunction() is deprecated. Use newShinyFunction() instead.');
When called, util.deprecate()
will return a function that will emit a DeprecationWarning
using the 'warning'
event. The warning will
be emitted and printed to stderr
the first time the returned function is
called. After the warning is emitted, the wrapped function is called without
emitting a warning.
If the same optional code
is supplied in multiple calls to util.deprecate()
,
the warning will be emitted only once for that code
.
import util from 'node:util';
const fn1 = util.deprecate(someFunction, someMessage, 'DEP0001');
const fn2 = util.deprecate(someOtherFunction, someOtherMessage, 'DEP0001');
fn1(); // Emits a deprecation warning with code DEP0001
fn2(); // Does not emit a deprecation warning because it has the same code
If either the --no-deprecation
or --no-warnings
command-line flags are
used, or if the process.noDeprecation
property is set to true
prior to
the first deprecation warning, the util.deprecate()
method does nothing.
If the --trace-deprecation
or --trace-warnings
command-line flags are set,
or the process.traceDeprecation
property is set to true
, a warning and a
stack trace are printed to stderr
the first time the deprecated function is
called.
If the --throw-deprecation
command-line flag is set, or the process.throwDeprecation
property is set to true
, then an exception will be
thrown when the deprecated function is called.
The --throw-deprecation
command-line flag and process.throwDeprecation
property take precedence over --trace-deprecation
and process.traceDeprecation
.
Type Parameters Jump to heading
Jump to headingT extends Function
Parameters Jump to heading
Jump to headingfn: T
The function that is being deprecated.
Jump to headingmsg: string
A warning message to display when the deprecated function is invoked.
Jump to headingcode: string
A deprecation code. See the list of deprecated APIs
for a list of codes.
Return Type Jump to heading
The deprecated function wrapped to emit a warning.